I really don't think they can limit who can download their releases with their license.

>If you distribute any portion of the software in compiled or object code form, you may only do so under a license that complies with this license.

>each contributor grants you a non-exclusive, worldwide, royalty-free copyright license to reproduce its contribution, prepare derivative works of its contribution, and distribute its contribution or any derivative works that you create.

I'm not sure how their rules comply with their own license, and I truly don't think they do. They're granting additional restrictions to a binary they're distributing (if you download this give us money). They're just hoping to scare some contributors into handing over some cash.

Maybe some licenses do allow for this, but the one they chose for Wix almost certainly does not.