theymos mentioned that he may remove them someday but since he's too busy, it will take a while:
I don't think that theymos has not removed all animated avatars (disable them all) so far because he is busy. I guess that main purpose of theymos is giving prominent users chances to wear their animated avatars. The fact is not all animated avatars are annoying ones, so theymos likely want to give them chances to wear it. For current users who have been in campaigns and worn animated avatars, they will change their campaigns someday, and I believe that months later, the figure of total users who wear animated avatars will drop considerably.