You are blaming the victim again. Nobody chooses to be a victim. People should not have to use the ignore function to stop bullying from other adults. That doesn't always work either.
But bullies live for the reaction. If you take that away, they cannot play.
I agree with you that it's frustrating--really, really frustrating--because it does feel like you're letting them "win," but when their only purpose is to bait and make you miserable, the only solution is not to take the bait. Anyone who knows what a poster is actually like won't believe the insults, anyway.