When I close an app, I want it closed, not in standby or running background tasks.
It's just a different paradigm. It's not like quitting the app is in any way difficult (it's just cmd+Q which I actually find a bit too easy to trigger by accident sometimes), it's just Macs don't consider an app to be the sum of its windows.
Conflating closing a document window with closing the app seems like a strange constraint.
This is completely unintuitive, unless you are a long term mac user. Neither windows nor any of the hundreds of linux window managers work so unexpectedly.