It's there because businesses want it. Macs are used at schools and businesses and in order for IT people to protect its assets from lawsuits they use that button to enforce software compliance.
No, they already had that power.
See, now you’re changing arguments.
One of the reasons I don't have an iPhone because I want to own my device and chose which iOS I want and control the behavior of my device the way I see fit.
Enjoy that nonsense, then. To each his own.