Supreme Court's ruling practically wipes out free speech for sex writing online

So, while I agree that this feels foreign and wrong to me as someone who has experienced "The Internet" for so long, I can't help but wonder if we can separate that from how the offline world works.

I'm asking this in good faith.

Given that:

1. The Internet is not an optional subscription service today the way it was in 1995. Every kid and adult has 1,000 opportunities to get online including on the multiple devices every one of their peers owns, which a single set of parents has no control over. So "Just keep them off the Internet/control their devices" seems like a silly "Just" instruction.

2. The Internet is nearly infinite. The author of this editorial says "then install a content blocker on your kids’ devices and add my site to it". This is a silly argument since the whole point is that no one has ever heard of him/her and it's obviously impossible for a filter (let's just assume filters can't be bypassed) can "just" enumerate every inappropriate site even if it employed a full-time staff who did nothing but add new sites to the list all day long.

So given all of that, how do we justify how the Internet must operate on different rules than the offline world does? One can't open a "Free adult library" downtown and allow any child to wander in and check out books showing super explicit porn. I'd have to check IDs and do my best to keep kids out. It also seems like it would be gross to do so. If you agree with that, why should the Internet operate on different rules?

I'd also like to separate the logistics from the morality here. If you believe it's hard to do it without satisfying privacy concerns, totally true! But then the focus should be on finding a good privacy-respecting solution, not just arguing for the status quo.

RE Point 1. All it takes is one of those other peers' parents to allow them to view pornography and then that kid just becomes the porn-distributor for the school, just like some kids in my day passed around porno mags. In essence, nothing changes for the kids, but every single adult is at best inconvenienced and at worst at risk of government invasion of their privacy. Not worth doing, imo.

RE Point 2. They could just use a whitelist instead of a blacklist/filter. They exist already, after all. Fill it up with sites showing the wholesome version of the world you want your child exposed to and they can only visit those places.