What exactly caused Stick to kill Red again?

I remember Stick was angry with Red, but I can't remember why. I think he was mostly directly angry with Harley, and he felt too overprotective of his daughter and tried to force them apart. I also recall Stick calling Red a "traitor", but in this situation I do think it was understandable since she didn't warn her family about anything, however it was said that if Red said anything, Stick wouldn't have believed her but he was too prideful to admit it. He was furious with her, and rejected her, no longer calling her his daughter.

I just... I never liked Stick, even when I first read the SE. I understand that he didn't trust Harley, but he should have let Red make her own choice to he with him. He shouldn't baby her all the time.