I’m curious about why. The one law that had been overturned so far was on the basis of government compelled speech, because in addition to age verification, the law required porn sites to have a paragraph talking about how porn makes baby Jesus cry. I’m not so sure ID requirements by themselves are going to have the same outcome.
Right to Privacy is the first thing to come to mind. It's worse in that this is not the federal or state government collecting data, it's a private enterprise. After that, there are frankly glaring Freedom of Speech infringements here, as the definition of obscene content is hand-waved. You can talk academically about making crystal meth on YouTube, but somehow specific content is restricted, not due to the protection of civilians, but due to individual tastes.
None of this falls under the purview of the government of the United States. I'm betting it's a rather damaging election year shenanigan.