You can submit your game however you want I believe, though, do be warned, differing, unusual methods tends to scare people away, and you may not get as many plays.
But pretty much if you can export or share your game in someway that can 1) be put on itch, and 2) all platforms, or the 3 main ones, Windows, Mac, and Linux, can play, then you're following the rules.
Well, I can't say that for sure, but I don't really know of people snitching out someone who broke just one, not-so-drastic rule. I'd reckon you're pretty much fine, there have been people that do this all the time. Though, you definitely won't get as much plays, as Mac players do make up a significant demographic it turns out
So, thought it is against the rules, it's not that big of a deal, and it effects you more than everyone else, so I think it'll be fine.
