I've worked in plenty of mixed sex places where the same behaviour in men would NOT be called bitchy.
I think there's more to it though than the 'women are bossy, men are assertive' trope, personally.
Men just don't seem to get as worked up as women do about petty things, IMO. I know it's anecdotal, but there just isn't anywhere close to the amount of moaning we see on AIBU on any men's forums I've been on (which is quite a few as I'm into cars, kickboxing, and lifting weights, which are all pretty 'macho' hobbies).
And it's not just that. Studies show that women are less likely to help other women who are senior to them, and conversely it seems that many women who succeed don't feel obliged to help others navigate the same path - e.g. I've read loads of posters moan about female bosses who've been less sympathetic than male bosses in accommodating parental duties.
I'm not slating women but I think too many posters have rose tinted specs through which women can do no wrong and are always the long suffering victim.