They don't find them sexy, but attractive.
Its more of a confidence and sense of stability and security.
If you notice, a young dude with a dad bod is a slob, lazy or something unattractive.
A older man with a dad bod is

to most women. It's not something they are going to scope out at the club or beach or vacation. But in any other situation where they see a man working or comfortably living with a dad bod especially doing "dad things" its something attractive about it to them.
Especially younger chicks, and that just loops back around to security and stability.