If you see a Hubber with a very low Hubscore, it suggests he or she has broken the rules somewhere.
Most likely, their Hubs are not original. The other common reason is that they join HubPages and go on a "following" spree, thinking it will somehow earn money. They can get lots of followers that way, because some people are silly enough to follow back, without even looking at the person's profile.
If you follow too many people, HubPages will penalise you heavily.