Because we gave it to them. The Corona Cows, at any rate – who are willing to mosey down any chute, as directed. Moo! Mooooooo!
It is the Universal Reason for Everything now. No work, no job, no money – no movement, even. Unless you are "essential" – which of course almost of all of us who aren't government workers aren't, as defined by government workers. It's a nice business to have the power to decree yourself "essential" – and immune from the life-ending restrictions imposed at gunpoint on the Corona Cows.
Maybe we should stop being cows. The way is easy. Stop being cowed. Take a stand. Go outside – and go for a drive, even if you don't need groceries and are not "essential" in the eyes of the New Mussolinis.