I think the letter gives us some indications about one factor that holds the behavior in place, and indeed may even in effect spread it. A foundational problem, one can see from the letter, is a pervasive lack of respect for women.
This lack of respect shows up in the 34 responses the writer gets when attempting to talk about the problem. No where do we see “O my god, that’s awful. What can we do about it?”
I think the lack of respect can show up even more chillingly in the treatment that women as outsiders can receive. And here I certainly do not mean to suggest that only men can do this. Women can also inflict the damage described in this passage:
Bias thrives in unstructured environments, where objective excuses for hostility are available, and where stakes tend towards doling out in-group rewards rather than punishing out-group exclusion. When professional rewards are discretionary, distinction between in- and out-group membership is heightened, the perceived flaws or weaknesses of out-group members are exaggerated, members are blamed more harshly, weaknesses are attributed to the person (“she’s not very smart,” “she’s crazy,”…) not the circumstances, excuses are less available, and punishment is swifter and more severe. Withholding professional respect, excluding women from philosophical conversations, refusal to acknowledge their contributions or minimizing their significance in favor of those of male colleagues, are all examples of discretionary rewards that even the best-intentioned philosophers are prone to deny women in informal settings. The presence of a male philosopher displaying overt hostility or aggression towards a female philosopher licenses further in-group hostility towards her, and where an objective rationalization is available for explaining this behavior (he has an objection to her argument, say, or she behaved somewhat inappropriately, etc.), it is often taken to justify this response. Women philosophers thus also suffer judgments that are harsher than their male colleagues’, more hostile, quicker and crueler dismissals of their views, and these judgments are multiply-reinforced by even their well-intentioned peers (my stress).
One particularly awful fact is that once one is positioned as an offending outsider, the complete lack of respect may be communicated to younger scholars. “O, she is just awful,” even if, for example, she has been chosen by peers for leadership positions, is generally described as at or near the top of the profession, and so on. The lesson here is: No matter what sort of reputation she manages to get, she does not deserve the sort of respect we give our male colleagues because she is a feminist, or she behaved in appropriately, etc. Junior scholars may not need to learn this behavior by example; they may be instructed in it. And so it goes on and on.
One problem for women who get this sort of treatment is that Equal Opportunity people may not see that it is gendered and so an offense against Titles VII or IX. “The department has a lot of jerks, but being a jerk is not illegal,” they may say. However, being a sexist jerk who is creating a hostile environment for a woman is. So it is well to go to any meeting to complain with a list of the kind of gendered cliches that show up in denegrations of women. Here’s the start of one and a few references.
So, supposing I’m right about the problem, what do we do? Suggestions, biblios, etc., are very welcome.