Eh, if you amend that to games where it matters in competitive, I’d agree mostly.
Though, being real, as long as they are willing to listen, and follow the instructions via voice, a mic isn’t necessary. To the contrary, if you have a good organizer/leader, everyone else wasting time responding during a match makes a mic a drawback sometimes.
Yes, it does mean that if you don’t have/use a microphone, and you aren’t willing/able to do what you’re told, you can fuck right off. You can’t work as a team and make independent choices if you aren’t going to communicate about them.
But this doesn’t apply to every PvP game. There aren’t a lot of truly competitive (as in the outcome matters, and the mode can’t be effectively played as a group of individuals rather than as a team) games that it doesn’t apply to, but they do exist.