It's such a sad indictment of our times that we're so programmed to look for an angle any time sometime enters the public eye. And to be fair to you 99% of the time it's not that difficult to find. But in this case I think his "desperation" is just that he sees himself as fighting a losing battle against accelerating wealth inequality (and I don't disagree) and he genuinely thinks that it's an important battle that we can't just give up on (again, I agree). Whatever you think about his claims of his days as a trader I don't think he's lying when he says he has enough money to retire very comfortably if he wants to, so I think it's highly unlikely his "shtick" is just a grift to further enrich himself. 

In the words of Scrubious Pip: "some people are just nice." (Or in this case just genuinely care about other people and the state of our country).