Question: Should a men not voice an opinion on women's issues?
Identity fallacy. It's when the argument is dismissed based on the arguer's social class, race, gender, etc:
That kind of logic can be taken to absurd conclusions. Should one be a dog to argue for animal rights? A cow to argue that killing animals for food is bad or acceptable? a moral philosopher or bioethicist with credentials and who is trained in their field has a far higher probability of underatanding gender-related and female-related ethical issues than a feminazi whose only credential is "knowing what it's like to be a woman."
Here's an interesting article by Dr. Bo about common fallacies in the social justice movement: