You know that he already has stopped participating in the world championship organized by FIDE, right? The current 'world champion' is Gukesh Dommaraju, who took it from Ding Liren the year before, but of course Magnus would probably still be the world champion if he kept competing for it.

I think the point the poster was making, is that there is an asterisk beside Gukesh and Liren's world champ status. Nobody really thinks they're the actual world-champ, regardless of what FIDE says. FIDE failed to attract the best player, to even play.