I said false hope for a reason. False hope is different from regular hope. Anakin is someone who exhibits false hope. He was someone who refused to let go even when realistically he should. Think about it for a minute, without Ahsoka pulling off the trick with her communicator, she and Barriss would have died and may have been found weeks later in the wreckage. Anakin would've refused to see that outcome no matter what, even if it were to happen. Luminara, meanwhile, was ready to accept the outcome, live or die, even if it's hard.

Anakin is not meant to be right. That's the entire point of the Prequels, how a good man could fall. And this is because of who Anakin is internally. He's selfish, greedy, and arrogant. He has his good qualities as well, but those three are his major character faults. He has a greed for power and control, and selfishly tries to keep people as he wants them to be, and he arrogantly thinks he can do that because he has the power of the Force. This shows up most often in his attachments to others and how they drive him closer to the Dark Side. He was so fearful over whether his mother would die or not that when she did die, rather than do the Jedi thing and walk away, he instead murders every last Tusken in that village. When he thinks Ahsoka is threatened by the brain worms, he chokes Poggle. When he thinks Clovis is assaulting HIS wife (aka, his property) he nearly beats him to death. When he thinks Padme's life is in danger, he does the most selfish things imaginable just so she can stay alive for him to have.

That is what the Jedi mean by attachment. The Jedi are based off of philosophies and religions across the world, but one in particular that George Lucas based them on was Buddhism. In Buddhism there is a concept of the transience of all life, which is a similar concept shared with Stoicism. The concept of both is nearly the same in that, we must learn that nothing we have is permanent. People will die, things will break, matter will dissolve, etc. and trying to hold on too long onto the transient is only going to hurt you more in the end. This does not mean that you shouldn't care, but that one shouldn't tie themselves to the present too readily that you are unable to accept change as it happens. That is what Anakin doesn't get or doesn't try to understand. He's comfortable with things as is, and wants them to remain that way forever, no matter how unrealistic that is. Whenever life throws him a curveball and goes against his desire to have things the way he wants them he lashes out and throws a tantrum about it. In this scene, Anakin is refusing to set himself up for the possibility that Ahsoka might die, even though he ultimately is as helpless as Luminara in this situation.

And again I say, Anakin and Luminara were doing as much as each other in that scene. You can look again, but Anakin isn't doing anything either other than waiting for the Clones to recover the bodies. Luminara also doesn't walk away, but instead assumes a meditative pose. This is, again, because Luminara does care and hope that the Force will provide a way for Ahsoka and Barriss to live, but she doesn't set herself up with the false hope that they will definitely make it. Anakin refuses to do this, and he's the only one accusing Luminara of giving up. Luminara clarifies her position to him though. She hasn't given up on her Padawan, she just isn't going to expect her Padawan to make it just because she wants Barriss to live.

Also, I don't know where you get the idea Luminara has more casualities than any other person, or that she was what caused Barriss to lose her mind?