They rightly list Genesis as a paid framework EXCEPT it is GPL'd. That means, onces you have it, you can redistribute under the GPL. You could even fork it.
The Genesis folks are quick to point out that Thesis is not GPL'd so that makes sense. BUT, downloading Genesis directly from the makers is not free, upgrading is not free, documentation is not free and support is not free.
I find this model a little disconcerting. GPL once you have it, you can redistribute it with, say, a child theme you develop but closed in every other aspect.
Does that strike anyone else as funny?