Absolutelyl nobody thinks that the tiny amount of CFCs in athsma inhalers could possibly have any effect on the ozone layer. It is just too small an amount to matter.
This is an aesthetic decision. The US wants to put up a zero on the scoreboard, to show that it is using absolutely no CFCs, and athsma inhalers are one of the last things to eliminate. But there is no environmental reason to do this. We want to do it because it is pretty.
The fact that asthma sufferers will die in order to implement a pointless policy just because it is pretty does not matter.
It does make one wonder if there is any advantages for Big Pharma in this. Maybe my tinfoil hat is squeezing me brain too hard. Otherwise, it seems like a silly, nonsense ban as you suggest.
I hope DeMint can maneuver this thing and win.