Circus Freaks pg 32 (commentary) (Patreon)

From what I've seen of the sisters, they're greedy and mean, but nothing implies that they're completely heartless. They're just jerks to their opponents.

Newer episodes of the show may prove me wrong, but I wanted to have the sisters with a somewhat screwy morality compass, but not outright cruel. Glam does drop hints of who she wanted to be if she wasn't a performer.