No I wouldn't name my child after a family member who did horrible things, no matter how bad, because obviously I don't care for that person. However, if there was a reason for using that name, then I don't see how that would be a big deal. You would NOT be naming your child after that person. Example: You want to name your child after your mother (
Stephanie) who was named after her evil father (
Stephen), who are you naming your child after? Your mother or your grandfather? Obviously after your mother.
But if it's giving you the association of your evil grandpa, I wouldn't even consider using it. It's kind of an old guy name anyway... ;)