They're not wrong. Wikipedia co-founder Larry Sanger has been very vocal about its ideological descent into left-wing populism. He's used words like "propaganda." I used to moderate the Men's Rights page. Eventually I was blocked by some senior moderators (who also heavily moderated the Feminism page, incidentally). You can go and review the difference between those pages yourself.
The Men's Rights page now includes criticism of the movement in the summary section. Note how that is entirely absent in the Feminism page. Over the years they've stripped more and more useful information out of the Men's Rights page. Especially anything which portrays the movement in a positive light. Almost anything without a citation, for example. While this is technically within Wikipedia's rules, this level of scrutiny isn't applied to the Feminism page. Not even close. Take a look at the section for suicide on the Men's Rights page:
> Studies have also found an over-representation of women in attempted or incomplete suicides and men in complete suicides.
I mean, what the fuck? On a page for men's issues like suicide, the person who moderates the Feminism page added stuff about attempted suicide for women. Many other sections contain a similar tone of, "but women also..."
The real cheery on top is the byline at the very top of the article directing people elsewhere with a hyperlink. Because how dare you research a movement which isn't pro-feminist:
> Not to be confused with the pro-feminist Men's liberation movement.
You'll note no similar byline on the Feminism page, directing people to pro men's rights feminist movements.
I could go on, but you get the picture. Over the years I've heard from dozens of people who have experienced similar issues, and have either been blocked, banned, or constructively cut out of moderating the pages they've been passionate about for so many years. ALL of them cite the same reason: ideology. Wikipedia long ago abandoned truth. Ideological compliance is now baked into the complex moderation structure. You would be horrified to learn how much is deleted and suppressed now. Just take a look through the moderation logs of any politically contentious pages for a seriously eye opening experience.