I do understand it. These are browsers that they decided during development that are not supported. Not supported means not tested by a full QA team for months. And users are generally stupid, soba simple warning (use at your own risk) is something that does not work.
So they decide to just not support the other browsers.
To be clear, I am definitely not a fan of Adobe of this mechanism, just explaining.
No downvotes is a feature toggle by the way.