Number one, if you had your bike in shop, the only thing that I can imagine stopped him was an overzealous boss and an insurance policy. I had both, and we got yelled at like crazy if we lent out tools. Second point- lending out tools means tools get stolen. Plain and simple. You're a good guy, but they don't know that yet. And letting a customer use a chain tool does open them up to a lot of liability if said customer is one that thinks he or she knows what he or she is doing when, in fact, they've never seen a chain tool before. He or she "fixes" the chain, which separates and causes a crash. He or she then sues the crap out of the LBS that the tool was borrowed from.
All of that said, why the guy didn't take a minute to help you out is beyond me. Not like it's something incredibly involved, unless again it's an issue of liability. But still, not like he's going to document the repair. Big city life, I guess. I borrow tools from my LBS in Gallup all the time.