Don Lemon is firing back at Kanye West’s Grammy rant against him ... telling us he doesn’t get why the rapper had to throw a racial slur into the mix.

We caught up with Don about the situation, and he clarifies he was just trying to ask Kanye a music question on the Grammys red carpet Sunday -- so he has no idea where Ye’s claims that Don was behind the false reports of him getting booted from the ceremony came from.

But Don was clear one thing ... saying Kanye calling him a "k***" was totally unwarranted.

Don tells us he doesn’t like that word at all -- he actually believes it may even be a worse insult for Black people than the N-word, which he notes is commonly used in rap music.

Peep the clip, 'cause Don's also got some theories on why he thinks Kanye doesn’t like him, pointing to a past interaction as an example, and explaining how he was actually trying to do Ye some good in that particular moment.

Just to set the record straight, Kanye was actually an invited guest at the Grammys and wasn’t kicked out, but clearly, he thought Don was behind the false reports and took it out on him online.