I know a few sleep dictators, and they seem to be equally on the side of getting up early vs staying up late. A couple of people I knew in college would get very annoyed if you wanted to go to bed any time before midnight, or get up before 10 am. To the point where if you attempted to leave a gathering, they would call you out and attempt to shame you into staying longer. That gets old quickly!
My grandmother isn't really a sleep dictator, but cannot understand why people aren't all up by 7 am, even on weekends. If you ask her, she'll say something like, "Well, if you wait any longer than that, daylight's slipping by!". I'm a natural early bird, so I don't mind, but it was kind of irritating to have her call me super early on some Saturday thinking I should be up.
My mom is pretty funny. Although an early bird like me, she vigorously defends a person's right to sleep as late as they want (well, anyone except me. I should still get up early, for some reason). If she hears me telling my DH to get up, she'll scold me that he deserves to sleep in. It doesn't matter why I'm telling him to get up, or what time it even is!