Some men, not all, who witness this behavior against women would intervene on her behalf. These deviates even prey upon children and it's awful.
It's easy for me to say, you as a women can fight back by yelling at the offender or hitting him. Don't normalize that behavior by allowing it to happen in front of you. Chances are you are not going to get the evidence against the man, but it will definitely stop if you fight back. A truly angry women yelling at you is very frightening to man no matter how big he is. Be brave, don't put up with strangers preying upon you.