Well no, actually. Both halves of that statement are false.

Injecting ads will get you removed from the extension store if caught, while adblockers are advertised on the front page of the store.

Google's "Manifest 3" rules, vs. ad blocking, in Ars Technica.[1]

Did the JSON formatter with ads get kicked out of the extension store yet?

	▲	SquareWheel 5 hours ago \| parent \| next [-]
		Manifest 3 explicitly enables ad blocking through the declarativeNetRequest API. It's trivial to do so, and many blockers exist in the Chrome Web Store.
	▲	FergusArgyll 4 hours ago \| parent \| prev \| next [-]
		ublock origin light is featured in the chrome web store.
	▲	Legend2440 5 hours ago \| parent \| prev [-]
		Everybody freaked out about Manifest v3, but I'm running Chrome + uBlock and still not seeing any ads. Seems like a nothingburger to me.