The term code-switching comes to mind, but it's not a perfect fit. The linguistic term talks about it more as something that people will do when they aren't able to express an idea in a specific language or dialect. The other time I here it is when talking about racial inequality, and code-switching in that context includes how one dresses, talks, behaves, etc.

In the same fashion that folks can be normal in social settings but shitty online, I've often heard that abuse happens in private because abusers only allow themselves to be abusive in private. This sounds very similar to the concept of code switching, though is almost the opposite of what it usually means. I do not know of a term for it.

Long story short, you are the ultimate decider of how you act, and you are yourself in all contexts. Take responsibility for your behavior in all contexts, because it matters in all contexts.

At the same time, though, I am a determinist who views humans as animals running off the same reward systems as any other animal, and thus equally likely to be 'unconscious' of their problematic behaviors. The seed of self control, the very idea of autonomy and personal responsibility, needs to be planted in many people. That role initially falls upon the parents, then the teachers as well, and then the individual's community. If none of that occurs, then it is no longer any small collection's duty, but the duty of society at large. So punch Nazis - you're doing them a favor.