For starters, I'm unconvinced that the MRA movement exists at all outside the extended reddit ecosystem. Maybe this is because the movement is nascent, and decades hence we'll look back and see that it had to start somewhere. Or maybe it will blow over and decades hence we'll barely remember any of these conversations. Who can say?

To your direct question, in what way is the MRA movement...such as it is...anti-individualist or anti-humanist in my view? Any movement which sublimates choice in favor of society at least has an anti-individualist thread running through it. Consider the topic of differential incarceration rates...one of the several causes celebres for MRAs. Embedded in the framing of the issue are many of the assumptions that are shot through anti-individualist feminism. Inequality of outcome is a priori evidence of socially constructed bias, for obvious starters.

Along similar lines, consider the question of gender imbalance in various professions. To summarize uncharitably, the current conversation goes something like this in my view:

feminists: Women are under represented in science and technology because sexism. Sexism is bad.

mras: oh yeah? well men aren't teachers because they are seen as incapable providers, that's sexism, too. Sexism is bad, and you're bad for only caring about one kind of sexism.

This admittedly inflammatory characterization of the debate illustrates my view of both how the two 'sides' are anti-individualistic alike, as well as how I see the mens rights movement as kind of a reaction to feminism as it is currently practiced in visible ways.

I rarely hear the conversation that I would say is interesting in an individualist, humanistic way: why is sexism bad? I have this sense that it is, but I'm at least a tiny bit unconvinced.

So why am I here at all, given that I'm a pretty individualist humanist? Why not just leave all these semi-socialists to their own devices and get on with my life? Partly it's that I think there's something going on with sex and gender, but I haven't fully incorporated what that something might be into my understanding of the world. So I'm here to expose myself to many takes for my own benefit. And partly its that my own life experiences have have some similarities with people who have also been drawn into the gender-sphere, and the commonality is intriguing to me. I found this sub in the wake of that Scott Aaronson blog post, I fully admit that much of the experience he described resonanated with me on a very gut level. So here I am, participating in what I really want to be a broad, ranging, civilized, pleasant discussion of the topic with what I would like to be a wide variety of opinions represented. I am sometimes not disappointed.