not many of you understand how the report system works. Defending yourself is fine but using your KDA as a standing point why you don't suck is using it as a comparison to the other player. This turns from you defending yourself to you trying to belittle or one up the other person.
Basically, you weren't defending yourself, you were using your superior statistics to put down the other player.
Another reason your ban is justified is for how you called for your report. It is not bannable to say "Report [player name]". However it is reportable to tack on "... for feeding/trolling/being stupid." This is the point you crossed the line and is very clear when that happens.
As for your justification for fighting back, the mugger scenario is bad. The difference here is you can actually ignore said "mugger." You can mute them and no longer have to deal with their toxicity. Why bother defending yourself from those who don't give a shit about you? You cannot reason with a player who is toxic. They ignore what you say and will not calm down. There is literally no point in trying to reason with these people.
For finality, you should take Mindspeakers words into thought. While they come off as abrasive they are in no way toxic. You may not agree with their reasoning, but calling someone here on the boards toxic derails the entire conversation. Your post here is you wanting to discuss your punishment, not call out other players.