Machine Gun Kelly's worst nightmare is being called the best "white rapper" -- as we learned when he made it clear that he is the anti-Macklemore.
Our photog at LAX tried to give MGK some props for his skills on the mic, and it kinda backfired on him. Unsolicited ... the Bad Boy MC unloaded about Macklemore's latest track, "White Privilege II."
Check out his take on the song, but it's pretty clear Machine Gun doesn't think race has anything to do with people's opinions of his music.
In a nutshell, sounds like he's saying ... quit your whining, Macklemore.