Unfortunately, an extreme fringe position from a few people with decently wide media reach can be sufficient to establish something as "offensive". Once some people have said it's offensive, people who are more concerned with respectability will probably avoid saying it, which means the people left saying it will, relatively speaking, be less concerned with respectability, and therefore will try less and probably succeed less at being seen as respectable; the word will therefore acquire less respectable connotations due to who uses it, which will provide a stronger motivator for respectability-concerned people to avoid it, and thus the statement "that word is offensive" becomes a self-fulfilling proclamation. I believe a recent, strong example of this was when some people with very wide media reach announced that Pepe the frog was a white nationalist symbol.