I would caution about calling it a gender issue. I think it depends on the person. I'm doing very well in the one crit group to which I belong. And I'm a man (I checked just now when I went to the bathroom...)
I can only speak for myself, but I do think that many men are goal oriented (I don't mean to say women are not, but bear with me...) I know I am. I think some of them join a crit group for particular reasons -- they want to give and receive crits, to help them improve their writing, etc. Some crit groups I went to in the past were:
a) the group is too large. There were 15 people one night at one group I went to.
b) it takes too long. One group spent 3 hours critting two pieces. There's a queue for crits -- 4 weeks' wait. So you end up spending more time critting others than having your own work critted.
c) there's a lot of "ego hugging" and "group therapy" going on sometimes. Not that it's bad, but for those who are "goal-oriented" per se, they could see it as a waste of time. They don't need group hugs. They need results.
d) they spend a lot of time doing "group writing" -- workshops, etc. I think some men are intimidated by that, and also they wanted to get on with the crits.
e) many of the writers in the crit groups are not published yet. So someone could walk in, and be skeptical about the quality of crits from the group. For example, if he/she hears someone saying things like "change your saids to belloweds, laugheds, exclaimed, etc.", you end up questioning the validity of the crit group itself.
f) unlike an online group where, when you're a little bored, you could do something else (like getting something to eat, surf the web for a while, etc.) as others are critting each other, you're kind of "stuck" at a real crit group. You end up sitting there for 3 hours critting two pieces of work, and you're falling asleep half the time.
It happens. And after a while, you question "Is it working for me?"
There may indeed be some gender differences, but I wouldn't stereotype just yet. I mean it is true that in general, women are better listeners, and they are able to listen just for the sake of listening. It's more about relationship building, showing support and such, instead of solving a problem (thus a crit group could be run that way -- a great support group). But men are more prone to want to solve problems, and their crits might be along that line as well -- to offer unsolicit advice for YOU to solve your "problems" (what goes wrong with your writing...) Read the book "Men Are From Mars -- Women Are From Venus"... I think there're some truth there.
I think, again in general, a crit group is a big time commitment, and when someone doesn't get the results he/she wants from it, they'd decide not to come back. For me, these 15-ppl, long, group-hugging, lets-write-together sessions did not suit me well. But that's just me.