Except the checkbox is not called "prevent to run on M1". Actually, bringing up the iPad is the perfect counter example since unchecking the iPad checkbox does not prevent your app to run on the iPad, it just will run on the iPad as an iPhone app scaled.
I haven't seen any counterargument yet to what I said so far. I do get it, Apple's does whatever they want anyways, it's their decision, but at least they should own up to what they chose.
The checkbox does not say it prevents to run it on the M1 but states about the availability on the store, it's called "Make this app available", I can also help you by providing actual screenshots if you want if you don't believe me.