In a lease agreement, it is a common convention to pay a rental rate for one dwelling or "unit" in the building. Not the "entire building " containing said dwelling. If you dont like what other people do with their dwellings, pay their rent for them in exchange for agreements governing what they do therein.

Nonsense, if I owned the whole building I would say "my [more familiar term than 'building']".

Perhaps an example will put you at ease:

"Oh could you help me take these to my flat? I know they're heavy, but don't worry, my building has a lift!"

Substitute apartment and elevator if so inclined.

I don't understand what any of this has to do with the comment to which you replied.