I thought diogenes' comment was a clever commentary on the tendency to accept only the part of an idea that appeals to us, and ignore the fuller ramifications. It's very Western to approach other world views with a "cafeteria" mentality, choosing only those aspects you fancy, and combining them with other individual pleasant aspects from other, unrelated, or actually incompatible, systems.
For those who believe in such things, if something bad happens to you, that is karma at
work in your life, as well, connecting that effect to some cause that you initiated, in motive, thought, or deed.
That's the inconvenient bit: we want to think that we're "basically good people" who don't deserve bad karma. But the effect (something "bad" happening, i.e., bad karma) is the evidence to the contrary, in that belief system.
I'm not persuaded by the idea of karmic law: I think you were just a victim of statistics: by definition, a low crime neighborhood has
some crime. This time, you were the victim. Consider yourself fortunate that the thieves were such casual small-timers; accept that you cannot be quite as trusting as you would like to be, and begin to lock your stuff up; don't over-react and become hyper-vigilant and paranoid about every unfamiliar face.