It comes from not caring about positions, because at the end of the day they don't mean anything. Sexton is someone who plays with the ball in his hands, whether you call that a PG or an undersized 2 doesn't really matter.
Defensively, Sexton is also almost always going to need to guard the smallest guard or a spot up shooter with no other threat.
I’m addressing just offense. Yeah maybe I’m old school but when it comes to quarterbacking an offense, establishing a calming effect, taking control, and making the right play/ pass at the right time, I see the 1 as somewhat distinct. Think conley/ DWill/ stock. I don’t think sexton will ever be that guy.