I would say the Bitcoin users are quite heterogeneous.

Anecdote time: I use Bitcoin more and more and never gambled nor bought drugs (not that I oppose people doing any of those things).

A lot of people are willing to support Bitcoin simply for ethical motives. We want sound money and are angry at the bloody Fiat fraud. The fact that it's also so powerful at being a means of exchange makes that adoption take off. This is from the simple user/traditional merchant perspective. Bitcoin serves a lot of purposes.