I hate to play the devil's advocate here, but no else seems to want to.
Step 1: "We assess that Miranda is knowingly carrying material, the release of which would endanger people's lives."
This is what they are calling terrorism. This is why he was detained.
Step 2: "Additionally the disclosure or threat of disclosure is designed to influence a government, and is made for the purpose of promoting a political or ideological cause."
This is not the act, but the justification for the act. By claiming he's only doing it for political/ideological gain, this is a preemptive challenge to a Public Good defense.
He is, however, being still being harassed for not playing ball.