It just seems silly that he would put them in danger like that.
Why didn't Hagrid just tell them that he didn't do anything in the slightest to attack muggleborns when they were talking in the hut?
Why didn't Hagrid tell Harry & Ron everything in plain words?
In The Chamber of Secrets, when Harry and Ron come down to talk to Hagrid, their conversation is almost immediately interrupted by Dumbledore, accompanied by Fudge and shortly afterwards Lucius Malfoy. They only have time to exchange a hello, and a 'Have you heard about Hermione?' before being interupted.
Before this point, while Hagrid knows that he was falsely accused 50 years ago, he has no idea that he's going to be arrested and taken away to Azkaban immediately. He is completely blindsided by Fudge telling him he's going to be taken away right now to Azkaban and he's clearly shocked at the idea that Dumbledore's going to be kicked out as Headmaster as well.
So given these two sudden and unexpected turns of events, by the time he realized that he needs to tell Harry and Ron about the truth, it's too late to speak plainly or explain anything.
Did Hagrid know that Aragog would want to kill Harry and Ron? Did he know he'd be putting them in danger?
The answer is clearly no. Hagrid has consistently displayed a complete lack of ability to understand that the dangerous animals he loves are dangerous and aren't the fluffy creatures he sees them as. In addition, Aragog had so consistently allowed (perhaps even encouraged) Hagrid to visit that Hagrid had promise of safe passage to that region of the forest.
He considered Aragog to be a dear friend and as such he had clearly expected Aragog to show the same mercy to his other friends as well. Unfortunately he was wrong - he had misjudged Aragog's nature.
Still, there is no reason to believe that Hagrid sent Harry and Ron to Aragog believing they'd come to harm.
Hagrid, throughout the entire series, shows he does not understand that these creatures can, and will, hurt people. Hagrid was 100% sure that Harry and Ron would be completely safe in the forest because he always was. Plain and simple Hagrid loves dangerous things yet does not realize that not everyone has giants blood in them making them tough, strong, and partially immune to magic. Therefore he feels that if he can do something (since he also knows he's not highly intelligent) anyone can.
Hagrid had no reason to believe they would be hurt by Aragog. After all, his children had never hurt HIM.
Aragog had clearly always told his children not to harm Hagrid, and Hagrid may have assumed, incorrectly as it were, that he'd extend the same favor to his friends.
Aragog did not.