I can't speak for all women, but most of the times I have attended trading groups, there is some man there who volunteers, without my asking, to 'advise' me. I don't think it's a pickup thing; I am too old for that. If I am attending a group for the first time, they simply assume that I am ignorant or intimidated. In truth, it's usually me who should be teaching them, but no matter.
I do brush things like this off, but I assure you that many other women would be pissed off and never return. We are, in general, sick of the tacit assumptions that we are less intelligent, less able, more timid, etc. These little presumptions happen to us every day in subtle ways. I know they are usually kindly meant, so I try not to take them too seriously.
I'm still laughing about the time (years ago) when I admired Bob Pisani in a post on this board, and someone responded by asking me if I were gay. It never occurred to the person I might be female.
In one of the trading groups I attended, I met several new mothers who were chatting about trading iron condors between changing diapers. So, I'm thinking the women are out there, but are just not forthcoming about their presence, or perhaps they are too busy doing other things to interact with other traders.