The same way I evaluate my doctor to be doing a good job - trust.

Your experience in life will always represent a tiny tiny fraction of one percent of all experiences. If you require a "see it to believe it" approach, you will live and die closed-minded.

That does not mean I need to blindly trust feminists, however.

I don't trust my doctor, or any doctor. I do my own research and if anything seems fishy I get a second opinion.

but then, maybe I can trust a statistically relevant sample of doctor on the basis they are objectively and scientifically trained, regulated and liable?