Sure, but you can make some reasonable guesses from other available sources, including his own statements. But his motivation is not really the issue we were discussing - it was whether the government just up and destroyed Lavabit on a whim. You said "it doesn't change the fact that US killed it since the government wanted to have access to all users' data without any restrictions and warrants." It doesn't change the fact because the fact is not a fact.
However you want to interpret his actions, there's little doubt that Lavabit's grief was entirely self-inflicted.
