Is there a way not to be banned from saying those three words?

So this happened about a week ago. I was playing a game where we all did rather poorly, including a Trundle who lost lane to a Nasus. I forgot if he got camped a lot or whatever, but that's not at all what's important. As we all know, after a while, you can't beat Nasus 1v1, and sure enough, Trundle gets killed in a duel. It's never a matter of if, but a matter of when.

So when I saw it happen, I made the obvious comment and warned not to 1v1 Nasus anymore. his responds was the only thing he typed and said that entire game, and I remembered the exact words said because of how much it surprised me.

"Kill yourself, retard."

I've heard the stories and seen the laughable "I'm innocent" threads on this forum, but this was first time anyone ever said it to me. Naturally, I reported him for saying, and I remember hearing countless times that Riot has a zero tolerance policy on those 3 words, which is more commonly said in letters, but I digress.

But here's the thing that concerns me. I've heard so many stories of how Riot ban people who say such an obviously dumb thing, yet looking through the match history, I've found the guy is still playing games, so clearly he got around the system. I heard that there was a way for Riot to find this particular offensive easily, but that might have just been a rumor.

Is there something I'm missing? I just would've thought this guy wouldn't have been an exception to something that obviously should never been said to another person under any circumstance or context.

Edit: By the way, I've already realized the actual banable words are technically 2 words, but you get the idea.