Odds are they just didn’t test on older versions. It’s one person building an app and they’ve made it clear it’s a beta. There’s no reason to be cynical about it, or to launch into hyperbole.

I understand your point of view. But supporting previous system versions requires resources and time that I don't have at the moment. But this is one of the goals to be achieved.

You know, you don't have to buy anything new. It's not a violation of your principles to buy a used Mac from 2017.