If everyone just votes for their own self-enrichment, then Steem's rewarding function is pointless. People are just paying themselves with their own money.

If some people vote for self-enrichment then they are doing so at the expense of anyone who is gullible enough not to.

I happen to think that a major function of Steem being completely pointless or a way to gain personally at the expense of other stakeholders is bad for Steem.

Sure, this isn't entirely objective but it's somewhat close. The logic is solid.