Opera has some content blocker built in. Rightclick on a website and select "Block Content". It supports wildcards. I guess most people who use content blocking have Adsense blocked. You can disable it per-site too (rightclick -> site preferences).
I too suspect a high number of Opera users to be very technical experienced.
Also I think Opera users are more prone to be quite cautious about being tracked online. I know several guys who stopped using Firefox and went to Opera since Firefox so prominently bundles Google with it.
Last but not least, choosing to use Opera is an active decision. IE/Safari/Firefox (Ubuntu etc.) are default browsers. Opera is not. So there is a high chance that the user uses it for a specific reason. Not something "John Doe" would do for "his internet".