Sure, it’s the L in GPL that gives everyone the right to use GPL code in their product under certain conditions as spelled out in the license.
Nothing in the license precludes the sale of such a combined work though, as in your devil’s advocate query.
I’m not even sure where the confusion or disagreement is in this sub-thread to be honest. The license is short and fairly clear; there’s ample additional “what does this mean for inclusion of GPL code in commercial products?” FAQs and a fairly large body of commercial products openly marketed which include GPL code in them.
Nothing in the license precludes the sale of such a combined work though, as in your devil’s advocate query.
I’m not even sure where the confusion or disagreement is in this sub-thread to be honest. The license is short and fairly clear; there’s ample additional “what does this mean for inclusion of GPL code in commercial products?” FAQs and a fairly large body of commercial products openly marketed which include GPL code in them.
[0] - https://www.gnu.org/licenses/gpl-faq.html#GPLCommercially