Riot (obviously) doesn't actually claim anything of the sort. I understand you may be confused and angry after a punishment, but you have to realize it isn't because of something another player did, it is only because of what you yourself did. Retaliation is not an excuse to be toxic and make the situation worse; you just become another problem to the whole team, who now have to deal with the first guy and the one trading insults with him.
While it's true that less people are punished for gameplay offenses than chat ones, here are some reasonable explanations and unfortunate inevitabilities for this;
- Because toxic chat is just way more common than inting/trolling etc.
- It's a lot easier to prove someone said something negative than to prove someone's bad Anivia wall was intentional.
- The player has a history of positive behavior. This applies to chat as well.
- Intentional Feeding Detection is relatively new; Riot is not done improving on these systems.
Don't place the responsibility of one person's actions on someone else; each is responsible for his/her own behavior and nobody elses. Muting and language filters are not excuses either; once someone is forced to use these against you, you've likely already become a problem. Muting is to halt further chat abuse from a player, while reporting is to help do so for all others in future games so that muting isn't even necessary.
