Chat Restricted for Defending a Friend

Starting off in champion select, I was playing with 2 of my friends, one of which bans kayn pretty much every game. So, he banned kayn, and it was in the last few seconds of the timer so he didn't realize someone had him selected. He in no way intentionally banned the person's champion, and they didn't seem to mind much so everything was cool. Fast forward to in game, the person decided to play xin zhao instead and wasn't doing very well, and decided to bring up how my friend (playing morgana) caused him to do badly because they banned kayn. Xin stressed that morgana must have done it intentionally and said we were trolling. I defended my friend, saying that it made no sense to say everything was okay before, but now blame us as soon as he does badly. Xin continued saying we were trolling because we didn't want to surrender when the rest of the team wasn't doing very well, even though we were still doing well and thought we had a chance. Xin started refusing to group with us and ignoring the enemies coming into our base, so I told him that he was trolling because he was giving up, and we were legitimately trying to play the game. Here are the chat logs riot gave me for why I was chat restricted:

Game 1 NinjaCharizard: rip NinjaCharizard: ty NinjaCharizard: why NinjaCharizard: stop going so deep just farm up dude NinjaCharizard: just farm NinjaCharizard: bot lane was gonna go in you shouldnt have chased NinjaCharizard: just play passive NinjaCharizard: bot in winning hard NinjaCharizard: *bot is NinjaCharizard: ok well farm as much as you can without dying NinjaCharizard: thats all u can do rn NinjaCharizard: its ok NinjaCharizard: dude dont try to bring that shit up as if you lost just cause you didnt get kayn NinjaCharizard: it was an accident NinjaCharizard: what reason does he have to ban your champion NinjaCharizard: LMAO so it wasnt a big deal then, but as soon as you feed its his fault NinjaCharizard: sure buddy NinjaCharizard: youre the troll NinjaCharizard: ^ NinjaCharizard: reporting you for attitude NinjaCharizard: i have my own vote for a reason lmao NinjaCharizard: im not surrendering NinjaCharizard: complain all you want NinjaCharizard: idc NinjaCharizard: were not trolling> NinjaCharizard: if anything you are NinjaCharizard: cause youre giving up NinjaCharizard: thats reportable NinjaCharizard: so NinjaCharizard: i love how were "trolling" because were actually trying to play the game NinjaCharizard: ok buddy NinjaCharizard: idc NinjaCharizard: report xin trolling NinjaCharizard: youre sitting in jungle while they take base NinjaCharizard: hes been calling bot lane troll all game because morg accidently banned kayn NinjaCharizard: it was a literal accident NinjaCharizard: we apologized profusely

I can see that I had an accusatory tone when talking to him, but I really didn't say anything that was insulting whatsoever. I told him it was an accident that my friend banned his champion, that we didn't want to surrender, and that he was trolling because he was giving up. I'm really just confused as to how this amounts to a chat restriction, especially considering I've had no prior restrictions.