Gentoo has to take some blame too for not keeping all the kernels they maintain patched in a timely way.
How do you figure that? From what I could tell from the earlier post, the fix has only been backported to 6.18 and later, and as TFA indicates the distro's were not informed of the security implications of this fix. All distro's shipping a major kernel version from more than a year ago -- and that includes all LTS kernels -- are vulnerable, regardless of how "timely" their patch schedules follow upstream.
To be fair, I question the wisdom of managing kernels like that across all distros.
the baddies are looking at every patch anyways.