I may have misunderstood your initial comment. If you were only talking about attacking violent mobsters who wouldn’t let you pass or were attacking you or others then you would be acting in self defense and I misunderstood you. I thought you were talking about attacking anyone in the mob including those not actually threatening you with violence.
What makes things much worse is that your motives in such circumstances do not matter. It did not matter that Trayvon Martin was straddling George Zimmerman while punching him in the face and trying to bash his head in on the sidewalk.
Well, it did matter to a jury. But it did not matter to any number of scoundrels that prosecuted and wanted to railroad him.
I absolutely agree with you that a person should not just wade into a hostile crowd with the idea of inflicting harm on a bunch of individuals. But that is just a reflection of personal integrity and a sense of fairness and justice.
Those in positions of authority often DO NOT HAVE a sense of fairness and justice, because they also lack personal integrity. They are just as willing to persecute an innocent person as they are to prosecute a guilty one.
If you saw a group of young men trying to rape and maybe even murder a young girl, and by whatever means you stopped them, likely the very first thing that would be screamed at you is that you are a “racist”. Illogical and irrational, but they would do it anyway.