This jerk was in MM's face, cussing him out, accusing him of being gay and half-grabbing at his shirt (not touching, but half-grabbing), and Matt was gesturing him to back off and going like, "Hey. You need to sit down". Then, there was more cussing, and the guy did something like reach for Matt's crotch, and that was it. People nearby started rushing in between them, and Matt told this jerk he was about to get his butt kicked.
At this point, we couldn't see anything, but someone we know said Matt kept his cool, but didn't back down either, and some associates of the drunk guy walked the man outside.
I've heard all kinds of conflicting stories about this incident - about what the guy said to MM, that Matt had to be restrained, that there was a shoving match and all kinds of crazy stuff that we never saw happen. In spite of all that, it was clear to all, who was in the wrong here, and it wasn't Matt.
So the guy's friendly with gay dudes - so what? He's a friendly, down-to-earth guy.
There's alot of gay guys in the business and the arts in general, so maybe the guy's friendly or comfortable with them; that isn't an engraved invitation to grab his dick. If he blows these guys off, somebody'll probably call him a bigot, which he isn't.
Nor is Matthew McConaughey gay. Gay-friendly isn't gay.