The problem with "MRAs" is the communities that identify as MRAs which function and communicate in the same derisive way that /r/Atheism was lambasted for.
Communities filled with people who have generally had shitty experiences and been burned by women and the systems that favour them, who when talking about these issues are incredibly smug, commonly bitter, and sometimes even genuinely hateful.
And it's important to recognize the difference between the narratives that are put forward by feminists and MRAs in terms of signal-to-noise(stated aims + actions taken to achieve those aims, including awareness raising versus unreasonable/unacceptable practices like violence, threats, witchhunts, doxxing, etc) and with the added context of the history of these movements.
Classic feminism was fundamentally a good thing and redressed a great many wrongs, while flipping a few other wrongs around, it was overwhelmingly a sincerely egalitarian movement which had some of the modern feminist rhetoric at the fringes of the movement, which was unsupported by anyone not at the fringes of the movement.
Modern feminism has largely turned into a broad reaching lobby for women that banks on both the good name of classic feminism and the notion that women are still perpetually victimized by men, these two things are the main points of recognition. It's worth noting that while the general public overwhelmingly supports the notion of equal rights, <20% consider themselves feminists, which is likely down to a combination of the sentiment that classic feminism has run it's course and achieved it's aims for redress and the general population not buying into the current rhetoric, though this brand of feminism enjoys a lot of media and political support for reasons of political correctness and a limited awareness of what the feminist rhetoric has devolved into, as well as reasonably prominent voices in the media sincerely pushing the agenda themselves.
It also has an abundance of people behaving horrendously in it's name and touting messages that run counter to the PC narrative of modern feminism and that run counter to the sentiments of classic feminism, but has an abundant reservoir of good-will because of classical feminism acting as a counterweight of sorts.
The MRA movement has both the legacy of classical feminism and the rhetoric of modern feminism counting against it, in terms of general sentiments towards it's narrative.
In terms of aims it's essentially the equivalent of classical feminism for men, seeking redress of all manner of issues, from issues of child custody to support for male victims of crimes that the mainstream narrative says are near exclusively perpetrated against women.
When it comes to people misbehaving in the movement's name, it also has them in abundance, not in a majority by any means, but an abundance nevertheless, the difference between the MRA movement and feminism is that the MRA movement has no historical good will in it's favour, and so that misbehaviour does a great disservice because it both discredits the movement while reinforcing the counter-narrative of the modern feminist movement.