Why coaching in competitive games is immoral

I think most people understand that there's an agreement by default when you're playing a ranked game with someone online that neither of you is getting outside help during the match. But I will make the case that even if it's explicitly allowed in the terms of service *and* the victim won't know, it's still immoral.

It's not just that you're breaking the matchmaking system in the moment and harming your opponent's enjoyment by giving them a match much harder than they should've had. The problem isn't even just that you're adjusting the opponent's rating as if they lost a well-made match, perhaps causing them severe upset by making them think they're worse than they are. The problem is also that you're creating a long-lasting ripple in the game's rating system: since your opponent's rating is lower than their skill now, other people who play with them (or you) will have their rating adjusted inaccurately, resulting in less equal matches for everyone in the community for a long time to come. You're making everyone's experience less enjoyable except your own. A terms of service that allows the practice doesn't change how human psychology or rating systems work, so it can't make this okay.

Now, a lot of people will jump to the defense of the practice saying that if it's allowed in the terms of service (like it is for Prismata) then that's the end of it and I'm a snowflake for objecting. Imagine if the terms of service explicitly allowed hacking and disrupting the game. Would that make it okay, or would the right thing to do be to not hack anyway, because ruining other people's experience is bad even if it's not a contract violation?

Smurfing is similar since new accounts usually start at a very low rank, but at least a smurf only harms other people while it's getting up to its proper rating; the disturbance dissipates. Whereas if you get coached regularly (but not all the time) the ripple will never end because you keep producing it.

I don't object in the slightest to "co-op accounts" - separate accounts specifically for a pair of people to play. These don't mess up the rating system because they're indistinguishable from just one more skilled person playing consistently. They don't give other players poorly made matches and lower their rating inaccurately. Though the real solution if you want to play with advice is to play casual matches, assuming the game has it and the queues aren't dead as a doornail.