In a way, there is no "right" answer on this.
It depends what you think.
Some parents are incredibly liberal e.g. let their kids stay up late doing whatever they want.
Others like more boundaries and discipline.
And we can be "liberal" on some things, and want more discipline in others.
Personally, I would not like my child or teen up watching TV when everyone else was in bed, it seems weird to me. There's a lot of inappropriate stuff on late, and I think it just creates bad habits. 10 p.m. is quite late IMO for a 14 or 15 year old to be up on their own watching TV until whenever ...
I think one reason some of us "don't know how to parent anymore" is that things have changed so much. When I was a teenager, there were no smart phones, there were only 4 channels, and most of the TV was over by midnight. So, in a way, we have to make our own new rules as we go along. Its good to canvass other people's views, but in the end you have to do what you think is right. Don't forget, teens and young people post on here, not even parents, so they may be coming from a very different place!