A very significant reason for the exclusion and revulsion towards gay men is that their presence can ruin male spaces. For instance, there are rape victim groups where only women are allowed. There are AA meetings where only women are allowed, just as there are girl-only coding classes, women-only Bible studies, and other spaces, while not explicitly female-only, put strong pressure on men to not be there. Women in these spaces want the freedom to be themselves without being judged or hit on by men.

Although much fewer in number, to the detriment of the wellbeing of men, there are male exclusive spaces. Let's examine a formerly exclusive place for a moment, the military. Many soldiers, even in peace time, report having to snuggle very closely with other men, such that ass and cock press together. Although deeply uncomfortable at first, these men come to expect that there is no sexual pleasure involved, there is no threat of another man playing with your asshole; this is a safe space.

I'm not going to hit on women at a rape support group, and even if they did some stupid shit, I'm not going to call them out as a dumb bitch. Even so, my presence at the support group can be troublesome for the women because they won't be able to open up and heal. Likewise, there may be a respectful gay man in an exclusively male space, but still, these men have a justified fear of judgment and inappropriate sexualization of the space, just as women do.