Actually, if you surf the entire fandom, you’ll find that Rumpel and Belle are EXTREMELY popular. Robert Carlyle even commented on it in a recent interview. He talks about the fan’s response towards the end of the video.
The only people who don’t seem to like it are those who ship Rumpel with Emma or those who never really liked Rumpel to begin with. It’s kind of difficult to estimate the level of popularity of certain characters with just one site.