The founder of Lavabit was perfectly willing to cooperate with the US government, including giving up customers' data, until some point when he just reverted to childish behaviour.
I don't see anything childish about upholding his fiduciary responsibilities to his users and standing up to the agents of a surveillance state which far exceeds even the wildest dreams of the East German Stasi.
He was perfectly willing to hand over customer data before Snowden.
Had he handed over the requested data, just like all the data before, noone would have demanded any keys.