He is directly coded as a villain with a direct malicious, spiteful streak.

Most of the enemies on steven universe can be branded as mental patients, technically. People scared, confused, or (somewhat justifiably) angry. Hell, even the homeworld gems can be somewhat written off since their understanding of the word 'people' just doesn't include humans. That is racism that you can possibly cut through by being adorkably lovable.

Cipher has spent time with humans, seen into their lives, hopes and dreams….and he only sees them as tools for his own ends.

In all seriousness, Bill Cipher would make a terrifying SU villain. He's completely beyond the Gem's ability to reach, and Steven is the exact brand of good natured but dopey that makes someone incredibly prone to manipulation by someone like Bill.