I personally don't think there is a major problem here.
The two avatars, while visually similar, are considerably different.
Vs.
If he were using the exact same avatar, it's more of a problem, because they really are important for distinguishing people on the forums at a glance.
If I read a topic and someone posts in it, I see their name and their avatar. If they post in it again, I just see their avatar and assume it's the same person.
These are quite different, to the extent that I think you wouldn't too-easily mix them up.
It's on the same scale of all the people who use very similar looking avatars that they get from one thread, like "I'll make avatars for you" threads, or from fandom topics.
It would be nice for Tee to respect your request, atleast by replying to it, but he really has no reason nor obligation to do so.
It's not especially disruptive, and it's not against any rules.
And meaning no offence, but your avatar is reasonably simple to edit from. And I can only assume that Tee simply likes the avatar to the extent that he wants one himself.
"Imitation is the sincerest form of flattery."
