"Constitutional" doesn't mean it's a good law, just that it is not prohibited for the state to make such a law. I personally don't like the law but I have a hard time seeing how it would be unconstitutional.
it should be unconstitutional because it's clearly a content-based restriction of speech, meaning that regulating it entails strict scrutiny. strict scrutiny requires Texas to use the least burdensome means possible to satisfy the state's legitimate interest in preventing minors from accessing obscene content - probably a home network filter appliance parents can opt into. this is what they held in Paxton v. NetChoice (iirc.)
instead, the Court contorted themselves into holding that adults have accessing content obscene to minors without furnishing their ID isn't protected speech. porn still is protected speech, but proving your age isn't protected speech. as a result, the law is content-neutral, not content-based.. somehow.
it was a low point for the Court - clear activist justices legislating morality from the bench.
Previously, these kinds of laws violated the 1st Amendment, but the changes in the composition of Supreme Court justices have led to different rulings.
