On the contrary. It makes you look strong when you resist.

The problem, then, is another issue we were trained into when we were small geeks being subtly bullied by the leaders of our school and camp social groups. When there's a social hierarchy telling you that you're at the bottom of the heap, and your interests are uninteresting and your behavior is weird, the thing to do is be silent and proud and don't let their scorn touch you. I understand that. I was there with you, in a completely literal sense.

But the sexual harasser on the train is a different situation. He relies on whatever training you have that keeps you there. If you get up and make the harassment visible to the rest of the train, you are in a public space, other people will see you and the harasser can't follow you without alerting the train to the problem. You need to move.