It's a turn off for a lot of people, and it bleeds into a lot of fetishes. It'd be like me posting scat in a vore thread. Loads of people don't like it, but there's a lot of content with both.
Eventually what would happen is that we'd have threads for every furry niche. Every fetish with a furry presence would have a furry version and a regular version with separate threads. Then you'd have subdivisions of furry threads for various types and so on and so forth. It doesn't help that the majority of furry art is kinda awful too.
This is kind of a problem with futa as it is right now, with dozens of threads with >100 posts.