Because it's an attempt to get a quick fix, rather than putting in an honest day's work.
On the scale of immorality, however, it probably isn't the worst thing.
What is terrible though, are gambling companies (I tend to get a ton of ads from them), that try to lure people in. They know that a fair chunk of the population are prone to addiction and they exploit that. To me, it's no different than getting someone hooked on drugs, creating a dependency, and then bleeding them dry.
