The Stig wrote:
Pike didn't agree with Kirk and Spock's interpretation of the PD, full stop. That the plan failed and Kirk was forced to expose the Nibirans to the Enterprise is beside the point.
I'm not so sure.
Pike is already riled up because Kirk lied on the report and then continued to lie to him face-to-face. He doesn't get "theatrical" until he mentions the natives seeing a starship rise up out of their ocean. Kirk states he would've filed a complete report if he hadn't had to save Spock by exposing the Enterprise.
There's the general party line of "we don't interfere". But I believe starship captains have a lot of latitude in deciding what constitutes interference. At least they do in TOS, because Kirk skirted the Prime Directive on more than one occasion.
You're forgetting that Pike and Spock argue about what constitutes 'violating' the PD. Since Pike is mad at Kirk for falsifying a ship's log, the matter is dropped. But it seems clear that, in Pike's mind, any interference with Nibiru's natural processes constitutes a violation of the PD.
Kirk was in trouble no matter what the outcome of the Nibiru mission was. As soon as he and Spock committed to their interpretation of the PD, they ran afoul of Pike.