It's not so much "he's treated as being right" as "his wrongness doesn't get the weight that it should."

For Steven specifically, The New Lars is the worst offender. He suppresses someone else's consciousness and takes over their body, and it gets laughed off as Wacky Shenanigans, with only minor scolding? Eugh.

Compare that to the guy who hit on Stevonnie. The show treats him as the creepier one, even though when it comes to boundary-violation, Steven's human-puppeting is in a whole other league.