The point that people are making is that while restricting overt internet porn does remove it from sight of a lot of kids, it will also continue to circulate as "samizdat" through whatever filesharing mechanisms exist. When I was at school someone got busted for distributing BBS porn on floppy disks, no network required. Now we have terabyte SD cards.

This samizdat is already in existence and the principal way my kids access inappropriate content.

Peer to peer, or peer to creepy pedo, is how the stuff gets passed around regardless.

Do you have any idea the sorts of things kids send via SMS?

Absolutely true. When I was a kid a few people got in trouble for drawing and circulating pixelated “porn” on their graphing calculators. You can’t stop teenagers from being teenagers.

hosts file isn't even the correct tool for this job. I don't know why this is being suggested a serious solution. I can add domain names and chose which IP address they resolve to. It can't even block websites.

If I didn't know any better I would assume you are spreading misinformation to put children into an unsafe situation

Yes I know this is technically true. One could use iptables, but it is easier for people (users) to do this instead of getting iptables / pf or whatever configured. It is one size fits all.