I suspect the parent post is aware of that but worded the post in a confusing way for a medium in which you can't use tone to convey added meaning.
By "Linux doesn't use GPLv3?", I think the poster meant essentially "But...? Linux doesn't use GPLv3".
In any case, the idea is a valid point. The GPLv2 and the GPLv3 are substantially different and it isn't that surprising that some people who were okay with GPLv2 terms are not okay with GPLv3 terms.
By "Linux doesn't use GPLv3?", I think the poster meant essentially "But...? Linux doesn't use GPLv3".
In any case, the idea is a valid point. The GPLv2 and the GPLv3 are substantially different and it isn't that surprising that some people who were okay with GPLv2 terms are not okay with GPLv3 terms.