I started wearing them under whatever the outer gear would be when doing anything athletic. I like the compression on my hammies and that my junk stays where I want it. It is also invaluable for holding a cup in place, for occasions when you need that. I don’t do anythng athletic anymore without wearing them underneath.
That was…
entertaining.
I wear compression shorts (UA and Nike) during ultramarathons, under my running shorts. Definitely improves comfort and subjectively seems to support the muscles.
I would have no problem wearing compression running shorts that are designed as an outer garment, I think they look fine, no different than cycling shorts (yes, I’m aware that there are people who wouldn’t be caught dead in those, either). I’ve got big muscle-y, hairy, runners legs.
I’ve also got several UA compression t-shirts which I wear running, I like the look (I’m in decent shape but certainly not “cut”) and they work very well - zero chafing, wick moisture extremely well, keep me comfy in both very hot and foul (cold, raining) weather.
And I’ve also got compression sleeves for my calves - again, works great during ultramarathons.
If someone else doesn’t like the look or feel or performance of the stuff they are free not to wear it. People who run those races really don’t care what anyone else is wearing and I really don’t care what people who don’t run them think. So that works out well 
Don’t like 'em? Don’t wear 'em.
Who gives a shit.
Don’t hijack yet another thread down this same tired old path. Have your opinion of the guy and keep it to yourself.
As far as this lady and passive MMA fan is concerned, GSP can wear compression shorts all he wants. He is a badass and looks awesome in them.
I have no junk to keep in place so I can’t comment on the wearing of these garments. But I would say if they are comfortable and improve workouts due to higher comfort, then wear 'em. If you don’t find them comfortable…then duh, don’t wear them?
If I’m not mistaken, we’re in IMHO right now. Not IOPHO.