As far as Atheism+ goes, it's an organized group spearheaded by people like Rebecca Watson who are outraged -- outraged -- at the behavior of atheists being insufficiently pro-woman and pro-social justice. Rebecca Watson in particular has a laser-like focus on sexism within the atheist and skeptic community, at the expense of the larger groups' nominal goals. She's responsible for the whole "elevatorgate" debacle, and responded to Richard Dawkins' claim that she was overreacting by going after Dawkins personally with this piece of loveliness.
It got worse.
Jen McCreight and PZ Myers have been circulating unverifiable accusations of rape, allegedly relied from anonymous sources, against big-name activists in the Skeptics movement, including Lawrence Krauss and Michael Shermer, who didn't happen to have jumped on the Atheism+ bandwagon.
Knowing nothing about this, "who didn't happen to have" looks unfair. Membership in Atheism+ wasn't distributed randomly, so it's possible people who chose not to join have different views on women.
A long blog post explains why the author, a feminist, is not comfortable with the rationalist community despite thinking it is "super cool and interesting". It's directed specifically at Yvain, but it's probably general enough to be of some interest here.
http://apophemi.wordpress.com/2014/01/04/why-im-not-on-the-rationalist-masterlist/
I'm not sure if I can summarize this fairly but the main thrust seems to be that we are overly willing to entertain offensive/taboo/hurtful ideas and this drives off many types of people. Here's a quote:
The author perceives a link between LW type open discourse and danger to minority groups. I'm not sure whether that's true or not. Take race. Many LWers are willing to entertain ideas about the existence and possible importance of average group differences in psychological traits. So, maybe LWers are racists. But they're racists who continually obsess over optimizing their philanthropic contributions to African charities. So, maybe not racists in a dangerous way?
An overly rosy view, perhaps, and I don't want to deny the reality of the blogger's experience. Clearly, the person is intelligent and attracted to some aspects of LW discourse while turned off by other aspects.