TikTok has recently started deleting cosplayer's videos, and banning creators of cosplay videos. TikTok is a great medium for cosplayers to have fun and express the characters they've created or love, they should be free to do so without being afraid that they're going to get permabanned or have their videos deleted. TikTok is meant to be a place to express yourself within the confines of the user agreement, it shouldn't suppress users simply because it's not what "most TikTokers" do. 

TikTok's tagline reads as "TikTok is the leading destination for short-form mobile video. Our mission is to inspire creativity and bring joy."
How can they inspire creativity when they're banning and deleting the creative side of cosplayers and videos? It's hard to bring joy to fans and creators alike when they're afraid that their videos are going to be taken down, or that their favorite artists are going to be banned. 
TikTok is known to support acting and actors, (TikTok donated $2 million dollars to The Actors Fund in light of the current COVID 19 pandemic (as of 4/21/20)), so they should also be supporting the actors and actresses on their own platform--not just the dancers and Vine-worthy comedy.
As someone who wants to start doing cosplay on TikTok, myself, the idea of being banned or having the videos I work hard on to practice be deleted is scary, and not something I want to stress about every time I post something.