I think that it's important to note that most MRAs and people in the "pick-up artist community" are guys who want to be having casual sex with lots of women, but aren't. These are young guys, usually under 25, who feel left out by seeing all their peers have sex and be in relationships. Because they're lonely and probably either live with their parents or in a dingy apartment, they don't understand their privilege at all. Always online they're told that they have it easier than women, but on their Facebook news feed all they see is girls their age having a good time. Men's Rights Activists use feminism as a target for their frustration, because they insist that it's the reason why nerdier, less charismatic guys (who may have been bullied in middle school and loners in high school) are hung out to dry. They blame their loneliness not on themselves, but on feminism.
A lot of MRA-type guys desperately want to be Don Draper-style manwhores, sleeping with huge amounts of attractive women and being praised basically just for being a man. Fedoras are (or were) popular among those circles because they hearkened back to a so-called "classier time", where men ostensibly could sleep with any woman just because they had a penis. Most MRAs recognize that the 1960s and earlier was an incredibly misogynistic time period, and because they no longer have the influence to coerce women into sex simply because they're men, MRAs feel like they're not at all privileged. Very few men in PUA communities are actually getting laid, but a handful of promiscuous misogynists inspire the rest of the people in the movement. Online MRA communities are a place for men to vent about how horrible they have it while also blaming feminists and, by extension, all women for their current plight.