Regarding the question of "what can you do", I had the experience last week of starting a new job. I had to read through the guidelines for the organization, which included a section on Equal Opportunity and Freedom from Harassment. Prominent on the first page:

"Harassment Defined 1. Hostile Environment Harassment prohibited under this policy includes verbal, visual, or physical conduct relating to matters of race, national origin, sex, sexual preference, religion, age or disability which is unwelcome to the reasonable person, and a. has the purpose or effect of interfering with a person's work performance b. has the purpose or effect of creating an intimidating, hostile or offensive working environment. "

Item 2 goes on to deal with more direct incidents such as "unwelcome sexual attention, sexual advances," etc.

I also looked at the relevant page on Wikipedia, to see what Wikipedia's policy is. (Sorry I don't have the link to hand to include.) It covered item 2. But "Hostile environment", item 1 on my workplace's guidelines, is not included.

Note too that item 1 is not limited to sexual materials; this is not identified as a "feminist problem" but as a type of behavior potentially relevant and unacceptable to anyone.

I would suggest that one reason that it's hard to get people to address this sort of situation is that it's not clearly identified at a high level as unacceptable behavior which creates a "hostile environment"

Mary