I wouldn't worry about the legality of programs like Tor. There is a community of people who care about privacy who develop and use these programs-- they are drawn from both the software development and academic sides of the industry.
Privacy software in the Open Source community now includes pretty good encryption which is available to anyone, as well as programs like Tor. No one is having legal problems from using this software and there are professional and legal groups who are working to keep it that way.
The
Tor Legal Faq (for server operators) may interest you.
BTW many of us who support the right to privacy for idealogical reasons want as many of you to use privacy technology as possible -- even if you don't need it.
If only one person protects their privacy, they will raise suspicion. But if everyone uses encryption and the Tor server, it is much better for everyone's privacy.