That's not actually true. You can run/install applications from outside the App Store as well. You can download the app from the developer's website but mac has extra protection steps if you want to play certain games. For example if I had to download a known application like minecraft, mac would not ask me if I still want to play as it was downloaded outside off the App Store but this does not really apply with less known developers.
Anyways I appreciate the alternative, I just got on my mac to test it out and it actually worked. Never knew itch had its own game executable app for its content. Thanks again for this!