What is considered toxic?

So I just played a game as irelia vs a malphite top. After getting a kill which was really close I said in all chat "XD" the malphite said in all chat "Dont think that you are good just because of this"

Later on in the game I had snowballed and was doing well so naturally I felt rather confident and silly so I tower dove their lucien getting the kill. I made it out of the tower with a bit of health when suddenly the enemy malphite launches across the lane with his ult and kills me entirely ignoring his thresh and taric and syndra who were fighting the rest of my team. Laughingly I said "Malphite so good, he ults just one person" I admit yes it was a snarky comment but it was more in light of malphites comment from earlier. it instantly resulted in him saying that he muted me and that he was going to report me for being toxic. (pretty sure he was the only one to report me) Aside from what I mentioned before the only other all chat comment I made was about feeling bad for killing thresh so often.

My question is was my comment really toxic? To me it doesn't feel like it was, but I want to ask others. If so I guess ill stop being so Id just like to hear from the community. What is the minimum of "toxicity" We all know easy examples of toxicity from the lyte smite threads, but what about the minimum?

TL:DR got reported for making a snarky comment based off something an enemy said earlier