Dana White -- I SUPPORT RAMPAGE ... When It Comes to Threatening Ass-Grabbers

They might not always get along, but UFC prez Dana White says he's GLAD Rampage Jackson punked an alleged ass-grabber last night ... and the dude's lucky Rampage didn't destroy him.

We broke the story, Rampage threatened to put a clubgoer in the hospital after the guy allegedly got a little too butt-squeezy with the MMA fighter's GF at a Hollywood nightclub.

Dana skyped into "TMZ Sports" today and told us ... he thinks ANYONE who violates a female deserves a good old fashioned ass kicking.

"If you're gonna go around and be a scumbag and touch people's asses that aren't your girlfriend ... you better make sure it's not Rampage's."