Why wasn't Poe told about Holdo's plan?

Question

(Last Jedi spoilers ahead, if you haven't seen the movie, please don't read on.)

So, fridge logic moment for me:

If Vice Admiral Holdo had told Poe Dameron about the plan to just hold on long enough to make a covert run to Krait, then Poe wouldn't have felt the need to send Finn and Rose on their little side-trip, and the code-breaker wouldn't have overheard anything nor sold them out, and the First Order would've had no reason to notice the cloaked ships.

I do understand that there's a lesson in there about following orders, even if said orders come from a pretty face in a pretty dress, but that's kind of an out-of-universe reason. What was Holdo's reasoning? Surely she knew enough about Poe to realize that treating him like a mushroom¹ would not result in anything good.

_{¹ "kept in the dark and fed shit"}

Answer 1

Initially because Poe Dameron has just been demoted from commander to captain for his hotheadedness; he's no longer in the top ranks. It's likely that Admiral Holdo is also trying to teach him a leadership lesson, citing Leia Organa's comment about hope being like the sun; just because you cannot see it at night (the darkest time) doesn't mean it isn't there.

There's also a clash of leadership styles, as director Rian Johnson explained who he set up the conflict between Poe and Holdo in this L.A. Times interview:

“[Poe] is a hotshot pilot, so you ground his X-wing and you face him with the question of bravado vs. true heroism, which is leadership. I started watching World War II movies, because you see that type of relationship reflected a lot in films like ’Twelve O’Clock High’ or ‘The Dawn Patrol.’ The fact that it’s a woman, and not only that, but it’s a woman who isn’t in a general’s outfit but has a real feminine energy, seemed like the toughest thing that Poe could come up against.”

This conflict heats up just as it appears that Poe has a chance to learn about the main plans: As he enters the command room, he sees that the shuttles are being fueled and he loses his temper. He accuses Admiral Holdo in front of the rest of the remaining command staff of being a coward and a traitor. Since a military commander cannot tolerate insubordination, Poe is ejected from the command area. (Note that this also follows his refusal at the start of the evacuation to follow Gen. Organa's orders to abandon the attack with the bombers.)

Thematically, Poe's failure to have hope in Holdo, along with the insurrection and the failure of Poe's alternate plan for escaping from the First Order sets him up for future leadership of the Resistance, at least in terms of Yoda's speech to Luke: "Failure is the greatest teacher."

Answer 2

If you have a plan that relies on sneakiness and staying hidden, you better don't tell everyone.

The hot-blooded pilot will tell his friends, someone listens in, and soon everybody knows the plan, including your enemy. The best way to avoid this is to tell as few people as possible.

Answer 3

Because Poe is a liability

Poe asked Holdo about the plan himself.

Poe: Vice admiral? Commander Dameron. With our fuel consumption there's a very limited amount of time that we can stay out of range of those star destroyers.

Holdo (looking busy): Very kind of you to make me aware.

Poe: And we need to shake them before we can find a new base. So what's our plan?

Holdo (finally giving Poe her full attention): Our plan, captain? Not commander, right? Wasn't it Leia's last official act to demote you, for your dreadnaught plan, where we lost our entire bombing fleet?

Poe: Captain, commander, you can call me whatever you like. I just want to know what's going on.

Holdo: Of course you do. I understand. I've dealt with plenty of trigger-happy fly-boys like you. You're impulsive, dangerous, and the last thing we need right now. So stick to your post, and follow my orders.

Poe doesn't follow orders and it has already cost the Resistance dearly. He was just demoted for such insubordination. And here he comes interrupting a superior officer to question orders, lie about his rank, and generally act like a male chauvinist. What commander has the luxury of coddling such a person in a literal life-or-death situation? Holdo rightfully recognizes Poe as a liability to the survival of the Resistance as she is tasked with commanding it.

Answer 4

What Holdo feared would happen was precisely what happened. She was worried that by sharing her plan too widely, that someone might flee the fleet in a pod and give the game away to the First Order. On top of that, Poe has repeatedly shown himself to be a massive liability and hardly the sort of individual you should be giving secrets to.

But Vice Admiral Amilyn Holdo had a plan: transfer all personnel to the Raddus, and then evacuate all hands to U-55 loadlifters outfitted with experimental “bafflers” designed to foil scans. The Raddus would be sacrificed, but 400 Resistance fighters would escape to the salt planet Crait, lying low until they could contact allies of General Leia Organa. Disturbed by a wave of desertions via escape pods, Holdo decided to share her plan with only a handful of loyalists: if the First Order learned of it from a deserter, the transports would be easy to detect and destroy. Her plan was undone by a security breach: Poe Dameron had sent Finn and Rose Tico to find a way to disrupt the First Order tracking system, and they had unwittingly revealed the scheme to the slicer DJ, who tipped off the First Order to save his own skin.

_{^{Star Wars: Battles that Changed the Galaxy}}