A pledge is a legally-recognized debt.
Sell them to debt collectors.
Sell them to debt collectors.
I bet you'd be willing to be a member of club that would have you.
;-)
A pledge isn’t a legally-recognized debt in all states, I don’t think. There is, however, a thing called integrity. I doubt Jim Robinson would even want to enforce a pledge made by someone morally opposed to a future contribution based even upon a misapprehension of the website’s intentions.