Hmmm. I wasn't aware there were Mary-Sue hunters. I don't really get why that'd be...well, even funny. Hell yeah, I wrote epic Mary Sues when I was eleven. Never posted to the internet, but for lack of opportunity not anything else.

I generally don't read fanfic that heavily features OC's. I read fandom for the familiar characters. I also try not to write OC's that much. This is actually hugely problematic in SGA because of absence of any real world building so few supporting characters.

But yeah, from what I've seen the Mary Sue issues is largely about misogyny in fandom. The other niches of fandom - slash, various subdomains of slash with extravagant kink, don't get called out for what is essentially a self-insertion that just happens to be more popular than other forms of self-insertion. (Self here loosely defined as 'author-originated'.)

Sometimes I come across awesome female characters, canon or otherwise. And I often find them totally out of place if they're OC's/totally out of character if they're canon. And that's because female characters in fandom rarely get to be awesome. I marvel at writers that keep canon women in character and make them awesome, because it's usually a feat the character creators didn't manage.