KIP MOORE decided to "unwind" after his concert Friday night in Fairfax, Virginia . . . by entertaining some frat boys at GeorgeMasonUniversity. 


Afterwards he posted Instagram videos of the good times. You can check 'em out here and here.


Well, somebody hit up social media suggesting his time would have been better spent performing at a more worthwhile place, like perhaps a nursing home.


Kip was furious and fired back in a series of Tweets. He said, quote, "I try not to waste my time on negative people that say dumb [crap], but in regards to the idiot last night and anyone else who wants to complain, our fans and us don't care what you think.


"We play for all walks of life, creed and color and we will continue. We play for children's hospitals, troops, charities etc., [but] that's never seen. If we choose to hang with a frat house that came to our original show then that's what we'll do.


"We don't play at an old folks home cause they wouldn't give a damn about us being there and would probably asked us to turn it DOWN!  We'll do us and you do you. To the fans . . . appreciate the support. See you soon."