Why not knock the crazy lady out?

because violence against women is wrong.

Two reasons. And, I haven't seen the film in fifteen years...

In the modern age most of us are aware that knocking someone out is VERY serious business. Even assuming you arrange so they do not fall in such a way to do further harm, a knockout is a serious concussion and as likely as not to leave permanent effects. Decent people don't do that to others if any alternative exists.

AND If a woman is attempting to sway a crowd against you with her crazy words, then, as a man, physically attacking them is not going to improve your position.