This is taking the unfortunate/entitled/nice/beta/shibboleth-of-your-choice males' complaint too far at face value - i.e., that they are sexually unsuccessful on account of being kind and prosocial.

People are really bad at measuring their own levels of altruism, which is hardly surprising. Those in this cluster of peoplespace are worse than average at reading social cues and others' assessments of them, and are apt to interpret "nice" and its congnates as "particularly kind and proscial," instead of what it usually means, which is "boring, but not actively offensive enough to merit an explicitly negative description." (Consider what it usually means when you describe your mother's watercolors or the like as "nice," sans any emphatic phrasing.) Likewise, we halo bad predicates onto those whom we resent - "jerk" is the male equivalent of "slut," in this sense.

What's creepy about this group is precisely the entitled attitude on display - that they deserve to enjoy sexual relations with those on whom they crush merely for being around them and not actively offending, or indeed in some cases for doing what in other contexts would be rightly considered kind and prosocial. This transactional model of sex is, well, creepy, and quite evident if you're specifically doing {actions that would otherwise be kind and prosocial} for unrequited loves and not people in general. The complaint is accurate in that yes, their being inoffensive and helpful isn't getting them laid, but the conclusion - that if they were jerks they would get laid - reveals a fundamental confusion. (I also think the PUA types are 100% right when they say displaying confidence is key, but that it's a bit confused to treat it as relating to dominance or women's preferences specifically - if you think you suck, others will assume you're right; this is the key to all sales work, and I've known a number of decent-looking women and gay men who aren't getting laid due to a lack of self-confidence as well.)

I have sympathy for these young men in that having poor native social skills and low self-confidence sucks, and, hey, I've been there. But they're not getting any approval for this, except when they meet up for affective death-spirals.