Don't get me wrong. Avatarfagging is a very sincere form of faggotry that mustn't be tolerated whatsoever. However, the rule of Avatarfagging requires a very distinct knowledge of Avatarfagging, mostly because of memes and culture norms.
Syke for instance is a meme/cultural reference to Star Vs. on /co/ its not really avatarfagging, unless its posted multiple times by a single Anon who specifically answers responses as Syke. An Avatar is essentially an image signature saying "Its me, the Skye Poster." The staff confusing Skye for Avatar posting is a staff that does not understand its own culture within the threads in their own boards.
Now, if I were to say post an image that is outside board culture, the only Anon to do so within a thread, and use images of that specific character in each of my responses, on a regular basis within a thread, then its avatar fagging.
You shoulnd't ban somebody for posting one image and calling it Avatarfagging, because it calls into question the judgement call and the motive in its deletion.
If 3/5 (maintain that ratio if higher) responses however are of a single individual character that has nothing to do with the text whatsoever, then its most likely avatarfagging.
Also don't bully /horse/ or the staff as a whole, its just a problem with the way that the foundation rule of Avatarfagging exists, and can often times be abused by cloud elves who have a penis to grind since it is a grey area/up to personal judgement Foundation rule, which goes against the very nature of a Foundation rule.