Yes. It is a definite ‘no’.
In your second paragraph you have missed what I was trying to say. My argument is: “we don’t want any part of it”. Full stop. However if it DID exist then we still wouldn’t want any part of it, but we would have to confront the fact that there are nuanced undercurrents of the thread that we would not be able to fully understand unless we chose to view avatars, which we don’t want to do. Therefore the only reasonable thing to do is not allow avatars in the first place.
As for your last point, it is true that egregious, obsessive discussions about avatars might indeed be slapped down as hijacking of the worst sort: hijacking where half the thread participants don’t even know what you’re talking about.
But it is the subtle, barely discernible effects that the avatars would add that is the real problem because these subtle nudges in the conversation would fly under most everyone’s radar, yet still change the tone and direction of a thread. And avatar-refusers would never fully know what was being hinted about in the sub-currents of the discussion. They should not be penalized for having the good sense to block avatars, and yet they would be. Not fair.
That is the reason to simply not allow avatars for anyone at all, because “opting out” leaves you at a disadvantage, and opting in is for many posters, unpalatable to say the least.