To its credit (though not everyone agrees), MS has spent a lot of effort making compatibility shims, basically doing other people's work for them, but they have no such obligation.
This is a different class of problem. In this case, a gatekeeper is asking you to use their service to distribute software through their channel, and that channel is governed by vague rules that may, in fact, be enforced on a whim. Further, the gatekeeper isn't being clear with the rules, and why you may have run afoul of them.
You sound like someone who's made the mistake of supporting Apple
Well, considering how hard Apple tries lately to make sure every piece of macOS software goes through them one way or another...
My point is not that they can't do it, my point is that they can't casually do it. It would be Real Work and it would risk major backlash.
Casually? The amount of effort and goodwill, say, Microsoft would need to spend to prevent me from installing $PROGRAM on my computer is significantly higher than the amount of non-effort a single extension reviewer would need to expend to click "no" arbitrarily because they are having a bad day.
How would Microsoft do it? Add legit software to Defender? Ship a Win10 update that disables a key API call $PROGRAM uses? Add "if program == $PROGRAM then exit" to the CreateProcess code? All possible, none casual. To the best of my knowledge they've never done something like this. I'm less deep into Apple land but I expect something similar holds on macos.