It seems the immediate crash was caused by gnome-shell trying to do execmem, I guess some JavaScript JIT thing. After enabling the allow_execmem boolean, gnome-shell no longer crashes.
I am not sure how, but it would be good to have better out-of-the-box experience with SELinux on desktop systems. At least it should not straight up crash, if the user is unaware of this boolean. The mindset sometimes seem to be that SELinux only provides benefits on headless servers. I don't see the logic in that, in fact, the use case where SELinux has most success is mobile devices (Android) and Fedora Desktop ships SELinux by default without much issues.
