Humble and classy people don't lose it from time to time?
Really, the "classless" part is their team was losing and Durant knew they weren't coming back and just didn't want to be on the floor any more. He wanted to be ejected. That's more frustration than anger.
NOPE, he's high-fiving fans on his way out, and I still can't see his tattoos. He's still classy and humble.