Yeah man, not sure where you're getting that idea from. I mean, I'm a guy. I can be extremely tactful, but when I lose my temper, will unapologetically say the most vile, vulgar, personal things and challenge you to do something about it. I'm a real hot head when I get to that point.
My wife, is the opposite. She won't say anything. My mom, just like me. My stepdad, extremely tactful to everyone but his family when he's flipping out, then he's the most f****d up man I've known. My male cousin, hot headed like no one I've known. My mother-in-law don't care what she says.
There are no correlations I can draw from males/females and tactful/loudmouth. It seems to be all over the map. It's a self-control thing and a temper thing I think.