As much I like where he is as a comedian, I only view this as necessary free game to younger artist coming up after him. As far as trying to sway public opinion to his side and somehow pressure any company to do what's "right", that's another thing entirely.
- you chose to agree to that guy using your joke
- you chose to play that card game
- you chose to sign that contract
No amount of public pressure is going to get you paid for a contract that you chose to sign, and thereafter chose to breach. Make smarter choices, continue to (loudly!) warn those coming up after you, stop crying about the loss and wallowing in those past mistake(s), and move forward.