I think that's really more a problem with facebook using a broad term for their app name than anything--but yeah; facebook has a habit of co-opting broad terms; my opinion is if we start using it first; we'll probably have it name recognition-wise, since our platform's far superior.
Beauty in this though is that there is no unified "threadiverse" platform; it's just Lemmy+Kbin+whatever comes next; and as such there's not much commitment to using any term over another--if "threadiverse" doesn't catch on; we'll get something better at some point