Why did Barty Crouch Jr. deny being a Death Eater?

Question

In Book 4, Harry Potter and the Goblet of Fire, Harry uses the Pensieve to see Dumbledore's memory in which Barty Crouch Jr. is accused of using the Cruciatus Curse and being a Voldemort supporter. We see him vehemently deny this and beg his father for mercy to no avail.

At the end of the book though, we see Voldemort praise him as one of his greatest supporters. We also see Barty Jr.'s disgust at the other Death Eaters for denying their own involvement with Voldemort and how he considers himself better than them because he was willing to go to Azkaban for his master.

My question is, why the disconnect? Barty Jr. now claims to hate the people who did exactly what he tried to do (and failed at).

Answer 1

I'm not entirely convinced that was what Crouch hated them for; consider what he says to Harry near the end (emphasis mine):

"I asked you," said Moody quietly, "whether [Voldemort] forgave the scum who never even went to look for him. Those treacherous cowards who wouldn't even brave Azkaban for him. The faithless, worthless bits of filth who were brave enough to cavort in masks at the Quidditch World Cup, but fled at the sight of the Dark Mark when I fired it into the sky."

"You fired... What are you talking about...?"

"I told you Harry... I told you. If there's one thing I hate more than any other, it's a Death Eater who walked free. They turned their backs on my master when he needed them most. I expected him to punish them. I expected him to torture them. Tell me he hurt them, Harry..." Moody's face was suddenly lit with an insane smile. "Tell me he told them that I, I alone remained faithful... prepared to risk everything to deliver to him the one thing he wanted above all... you."

^{Harry Potter and the Goblet of Fire Chapter 35: "Vertiaserum"}

Crouch's ire seems more directed at people like Lucius Malfoy and Igor Karkaroff, who bribed their way out of Azkaban and then basically abandoned Voldemort, more-or-less assimilating into polite society.

It's worth noting that Voldemort himself levels similar criticisms at the other Death Eaters during his rebirthing party:

"I smell guilt," [Voldemort] said. "There is a stench of guilt upon the air."

A second shiver ran around the circle, as though each member of it longed, but did not dare to step back from him.

"I see you all, whole and healthy, with your powers intact - such prompt appearances! And I ask myself... why did this band of wizards never come to the aid of their master, to whom they swore eternal loyalty?"

[...]

"It is a disappointment to me... I confess myself disappointed..."

^{Harry Potter and the Goblet of Fire Chapter 33: "The Death Eaters"}

While I agree with Rand al'Thor that, at the time of his trial, Crouch was likely scared out of his wits, by the time of Goblet of Fire I suspect he's rationalized his behaviour to himself; in his mind, he was presumably using every resource available to him to remain free, so that he could continue the search for Voldemort.

I'm sure it all makes a great deal of sense to him, which frankly is the most damning thing I can say about it.

Answer 2

Barty Crouch Jr.'s experiences changed his outlook on life.

Consider that he'd been in captivity for what could have been a long time, and guarded by Dementors. In such an atmosphere, even the most loyal of loyalists might be driven by terror and panic to deny what they believed in, clinging to the vain hope that they might be able to escape.

Here's the scene from the book (emphasis mine):

The Dementors placed each of the four people in the four chairs with chained arms that now stood on the dungeon floor. There was a thickset man who stared blankly up at Crouch; a thinner and
more nervous-looking man, whose eyes were darting around the crowd; a woman with thick, shining dark hair and heavily hooded eyes, who was sitting in the chained chair as though it were a throne; and a boy in his late teens, who looked nothing short of petrified. He was shivering, his straw-colored hair all over his face, his freckled skin milk-white. The wispy little witch beside Crouch began to rock backward and forward in her seat, whimpering into her handkerchief.

Crouch stood up. He looked down upon the four in front of him, and there was pure hatred in his face.

[...]

“Father, I didn’t!” shrieked the boy in chains below. “I didn’t, I swear it, Father, don’t send me back to the dementors —”

[...]

“No! Mother, no! I didn’t do it, I didn’t do it, I didn’t know! Don’t send me there, don’t let him!”

The Dementors were gliding back into the room. The boys’ three companions rose quietly from their seats; the woman with the heavy-lidded eyes looked up at Crouch and called, “The Dark Lord will rise again, Crouch! Throw us into Azkaban; we will wait! He will rise again and will come for us, he will reward us beyond any of his other supporters! We alone were faithful! We alone tried to find him!”

But the boy was trying to fight off the Dementors, even though Harry could see their cold, draining power starting to affect him. The crowd was jeering, some of them on their feet, as the woman swept out of the dungeon, and the boy continued to struggle.

_{-- HP and the Goblet of Fire, Chapter 15: The Pensieve}

What we see here could genuinely be a young and frightened boy, who's spent most of his life with a doting mother if not a loving father, and is facing the prospect of sending the rest of his life in Azkaban. That's enough to make anyone scream and beg for mercy.

Then his time spent in Azkaban, and in captivity at his father's house, changed him even more than he had already been changed by siding with Voldemort. He had no hope of being accepted back into the normal wizarding world; the only person who might accept him was Voldemort, and only if he truly proved his loyalty. He might have been less loyal to Voldemort before his trial, perhaps cozened into being a Death Eater by his older 'friends', and only became such a rabid supporter when it was the only option left open to him.

The ordeals he went through hardened him, and he ended up being contemptuous of those who were unwilling to go through such ordeals in order to prove themselves. How could anyone else claim to be a supporter of Voldemort if they hadn't proved themselves as utterly as he had?

Answer 3

He likely wanted freedom so he’d keep looking for the Dark Lord.

Barty Crouch Jr. is a very convincing actor. He was able to convince many skilled wizards, including Dumbledore, that he was really Moody. It seems most likely that his reaction at the trial was at least somewhat of an act. The Dementors undoubtedly affected him, but his claiming he was never a Death Eater wasn’t necessarily, or even likely, an attempt to forsake the Dark Lord - he could have been acting in the way he considered most likely to get him free so he could seek the Dark Lord.

“Then I packed up Moody’s clothes and Dark detectors, put them in the trunk with Moody, and set off for Hogwarts. I kept him alive, under the Imperius Curse. I wanted to be able to question him. To find out about his past, learn his habits, so that I could fool even Dumbledore.”
_{^{- Harry Potter and the Goblet of Fire, Chapter 35 (Veritaserum)}}

Barty Crouch Jr. seemed to be focused mainly on finding the Dark Lord, so it seems likely he may have wanted his freedom specifically so he could continue that. When he’s broken out of Azkaban, once he recovered from its effects, he’s intent on seeking out the Dark Lord and returning to him.

“Then I had to be concealed. I had to be controlled. My father had to use a number of spells to subdue me. When I had recovered my strength, I thought only of finding my master … of returning to his service.’

‘How did your father subdue you?’ said Dumbledore.

‘The Imperius Curse,’ Crouch said. ‘I was under my father’s control.”
_{^{- Harry Potter and the Goblet of Fire, Chapter 35 (Veritaserum)}}

In addition, he mentioned how the other Death Eaters who had gotten out of spending any time in Azkaban were free to seek the Dark Lord, but they didn’t.

“We heard the Death Eaters. The ones who had never been to Azkaban. The ones who had never suffered for my master. They had turned their backs on him. They were not enslaved, as I was. They were free to seek him, but they did not.”
_{^{- Harry Potter and the Goblet of Fire, Chapter 35 (Veritaserum)}}

It seems likely that finding the Dark Lord was also on his mind at the trial, and he may have been trying to avoid a conviction with the goal of continuing his search for the Dark Lord.