Humm yeah a huge fraction of it is illegal. In fact in some countries it is illegal to circumvent the restrictions imposed by the State on the internet. I am non trying to start an argument, but the concept of illegality depends on the laws and very often is completely disjointed from the concept of justice.

Is it illegal to buy drugs? Yes, in a lot of countries. Is it immoral? A lot of people think it isn't.

So, don't use the metric of the US judicial system to establish what should be considered illegal/immoral on TOR. TOR is a worldwide network and shouldn't be judged based on the laws of a specific country.