I hope your workplace doesn't use Teams. Everyone in that meeting will get a notification that you already started that meeting 15 minutes early.
For everything else other than arriving 15 min early at work, I agree. Your boss has no right to ask you to come earlier than your agreed time. If I had a boss like that I would make sure to leave 15 minutes earlier, since obviously I should be home 15 minutes earlier too!
Bullshit