taking part in a mass act of civil disobedience does involve taking a few risks in the hope of gaining something that matters to you. That's a kind of gambling.

At the risk of taking this much too seriously, that's actually the wrong way round - gambling is a concentrated, artificial version of "taking a risk in the hope of gaining something". Trying to achieve any goal involves taking a risk in the hope of gain; gambling, on the other hand, just gives a pure hit of the risk/gain combination without the goal or the achievement. That's why it can be addictive, I guess.