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.