It's pretty premature to be blaming this on bitcoin content. Google may do a bunch of bad things, but they want people to show ads except for a certain number of known categories - and with those they are upfront about it. They have real problems with clickfraud though, and for sure their algorithms get false positives. Combine that with ultra low traffic ("only making me pennies") and it's not worth their time to care about a identification specifically. In fact, this the best argument that it's not bitcoin related specifically - the site in question was probably too low traffic to have anyone with a pulse ever look at it.

What was your CTR? If your CTR was too high you'll pretty much get autobanned.