@BarrenPlanet @Gargron @bok_bok_ba_gok
That's not a "dark web", that's any website with a section that requires a login.
Websites have had such sections since the beginning of the web. Most business sites have them for internal discussions, for example.
As I said, if something nasty is going on then the authorities should be informed, but in the specific cases cited by the article the sites are in countries where the content is legal, so all that the rest of us can do is to block them.