There is _one_ legitimate use for a lock pick set: to unlock something you own that you've accidentally locked yourself out of. There are literally billions of uses for BT: every large public (legal) file that's currently distributed via centralized server.
Some people use lock picks to unlock doors that they don't have permission to much in the same way that some people use BitTorrent to transfer data they don't have permission to.
(Personally I know exactly what you're talking about, but trying to hang your case on an obscure sport isn't doing it any favors. The lockpick analogy is bad and a car analogy would serve you much better.)