[1]: https://www.gnu.org/licenses/license-list.en.html#NonFreeSof...
This sounds like cherry-picking to me. "If they decide to contribute back patches" is something that is not up to you -- and the same logic applies to copyleft forks just as much as it applies to proprietary forks (the quotes are not necessary, proprietary forks of lax licensed software are forks like any other kind of fork). Just because someone has used a license that gives users freedom should not be construed as it being a contribution to you.
> They typically have the generosity of making those available under the original permissive licence.
They also typically have the "generosity" of not providing source code to users, meaning that the users have no freedom when using the software. But hey, at least you got some marginally useful patches that probably aren't all that great. Yay.
Also, please note that some projects do dual-license their changes. I don't understand why you're so salty on this topic.