If we take that into account, Bruce's irrational behavior starts to make way more sense, beginning with his hatred for Superman. It doesn't just come out of nowhere; Supe's brawl with Zod almost kills a kid. And seemingly orphaned her, not unlike young Bruce himself. He manages to save the tyke, but clearly that pushed a button. You can see in Affleck's rage-filled eyes that he's funneling all of his trauma into hating the s**t out of Superman.
We also see Batman branding criminals, a distinctly un-Batman-like thing to do. But it's not just any criminals; it's human traffickers who have been enslaving teenagers. Again, Batman is acting out of character because kids are being hurt. When discussing Superman, Alfred remarks that the "feeling of powerlessness turns good men cruel." And it's clear he's not just talking about flying aliens.