Oh I agree. If anyone was being disingenuous it was dogsout, who pretended the relevant actual quote was about appointing a special prosecutor. It is hard to parse Trump's statement, which came in response to Hillary musing about what would happen if Trump were elected as anything but a "promise", so you got the intent right.

Hillary: If you were elected..
Donald: You'd be in jail.

He didn't at that point bother about the prosecutor, just that if he were elected, she'd be in jail. Not if he were elected and she was found guilty. Just a simple declaration of a future found in many countries with less of a democratic process. Become a leader, and jail the opposition.