Is this offensive?

Hi guys, I posted many discussions about player behaviour, and I want to know your opinion on a game I just had. I was playing Ahri mid, and went top to help our Yasuo vs GP, but GP killed Yasuo before I arrived and I missed E + my ult was on CD. He did his Q twice on me and I died. After that, he started flaming us in all chat with EZ NOOBS. I told him its not allowed and that he can get punished for that. Still, I CAN SAY EZ, EZ, EZ. Yes, all in capslock. But justice was on our side, he lost the game, and I wrote this into the all chat: Now say ez GP, what? No ez from you pleb? And I got reported for toxic behaviour. How the hell, is calling someone a pleb toxic, but to GP logic, ez isnt? In my opinion, pleb isnt an insult, its just a funny word.