I don't think that's a good explanation. The vast majority of people behind such initiatives don't come from underprivileged or victimized backgrounds.

It's more about this idea of being an advocate for the downtrodden - a good person fighting the racists on behalf of those without a voice. And because you're fighting the good fight, it's of course OK to make the oppressors uncomfortable or to bully them into submission.

Depending on your priors, this is either messed up, or it's messed up not to act and accept the status quo. Pick your poison, I guess.