Why do gay guys talk about pmsing, etc.?

I have many gay friends and sometimes when they are in a prissy mood, they will talk about how they are "PMSing." Or they'll say things like "I'm so bloated," or something having to do with having your period and really they hvae NO CLUE what it feels like! I dunno, it just annoys me sometimes. It's like... it's fine if they are feminine and love to be in drag, etc. but the period thing I think is taking it a little too far. I mean, I would never go around talking about having a wet dream, for instance because let's face it- I'm a woman, I have no clue what that's like! I do belive that man onbviously can have mood swings, but PMS is way more than just mood swings. Women out there, you feel me on this? LOL Gay guys- why do you pretend to go through this???