Those are the moments where I wish I had some mutant or special power to zap him with enough juice to make him take pause the next time he thought about assaulting some random girl on the street. Instead, these guys are never afraid. Because they know no one is going to do anything or stop them. They won't get into trouble. Even the authorities don't take this form of contact as assault. And you could try to attack him. But most guys are physically stronger and they know it and take advantage of it.
I was nearly knocked down in a bar once; some drunken slob struck me on the ass and lurched me forward. I was stone-cold sober. I marched back, after catching myself. I was going to return the favor - you know, cheek for cheek. But his buddies formed a bro-wall to protect their idiot. They cooed and soothed, saying he was drunk, he didn't mean it. Yeah, right. My a**. He meant it. They protected him from getting just what he deserved - a lesson on why you don't touch strangers. I considered complaining to the owners, the bartender, the guy at the door, perhaps call the cops. But I knew in my bones no one would do anything. He knew it too. Smug f*er.