The hard part about running a Tor node for me has always been that you're helping the bad guys just as much or even more as you're helping the good guys, make sure that you know what you are getting in to before running a Tor node.
And yes, technology can be misused. So can a hammer. Tor protects everyone. Who is to judge about what is "bad" and what is "good"? US Government? Google?
There's an estimated number of at least 10,000 bridge users EVERY DAY. I don't think any criminal would go through the pain of using bridges, so that must be people behind firewalls in totalitarian countries.
Also, if you're up to something not good, it's always easy. As a criminal you can buy bot nets, pay servers with stolen credit cards, etc.
Both untraceable, anonymous communication (what Tor provides) and the public distribution of previously confidential documents (what WikiLeaks provides) are controversial in this way; but it is far from clear that they "help the bad guys [as much as] the good guys".