So it's OK to ask if I didn't get an upgrade and bought the ticket outright? I mean, the guy I'm asking probably got an upgrade, so I'm not sure why I should care about his feelings (to use your thinking).

Interacting with other humans is table stakes when you're on a plane. If you really think someone asking you about changing seats is a violation of your human rights, you should probably stay home because you're going to experience much worse than that out in the big mean real world.