It might be public transport, but everybody agrees there's some written and unwritten rules on how to share public transportation. So again, I draw a parallel with someone creating noise and forcing everyone else to wear earplugs, obviously that's not ok.
Someone keeping the blinds open during a long trip while the cabin is dim/dark, that's just similarly rude in my opinion.
As mentioned, it's way easier to avoid introducing light and noise in the first place, rather than forcing people around to use an eyemask or plugs. Why would anyone use an eye mask anyways if they just want to watch a movie or read a book?
One can look through the window, peak here and there, but also look around and take a clue that if the cabin is dark and most people are resting/sleeping, maybe is not that polite to leave the blinds open.

anyways, this is an endless debate and will never come to resolution and that's ok
I've never asked anyone to lower the blinds, as it's in their rights but I do think in certain contexts it's just selfish.