Because hacking isn't magic. the internet isn't something one person can control. it's like the wild west in there, but on tor, free distribution on websites are really well protected. a vpn is a "computer" checkpoint, well , tor goes thru five of these wich makes it ALOT more complicated than regular websites on the clear web to track. Thats why illegal stuff like that are here on tor because tor promotes posting everything everyone wants, are protecting the people who make those websites.
