Luke's Predicament

Anonymer

Why does Luke get angry at Clem if she honestly tells Bonnie about how bad Luke feels about everything that happened after they escaped from Howe's?

Simply

He says "thanks a lot" because he didn't want everyone to know about it, he wanted to keep his feelings of guilt to himself, he seemed to trust Clementine enough to tell her but when she told Bonnie he probably felt a bit disappointed and mad, also because he is their 'leader' he doesn't want to seem like a baby to them, he wants to seem strong just like Bonnie said they all want to be alpha male and seem like tough guys

BlueShadiw

I guess he didn't want to show his true emotions about everyone that had died along the way, since he was practically the glue of the group.

Luke hasn't been shown to be that caring of lost group members in the past (excluding if you left Sarah behind "Well, I can't forget it.", and if you count it, Nick's death in Ep 4 "Fuck, fuck."). He didn't want to let everyone know how hard he felt that he failed to protect them.

Kordas

Because he waits to be alone with Clem to talk to her about how bad he feels about everyone that died. I think he trusts Clem the most. He needs to get it off his chest, because he's been supressing his emotions but he probably doesn't feel comfortable doing it around anybody else as he's practically glue of the group. So, he trusts he can talk to Clem, so if you choose to tell Bonnie about what he just said, he feels somewhat "betrayed". That's of course too big a word for what Clem did, but I think she trusted Clem to keep this conversation only between them.