I'm beginning to wonder if this isn't a scene where Kirk is deliberately baiting Spock to provoke emotion in him? I seem to recall that happening in TOS. "You green-blooded so and so" etc.
Maybe Kirk is trying to prevent Spock being too emotional in reacting to some action or threat against them, and he's doing this to make a point and 'snap Spock out of it' for a moment.
Thus Spock is not wigging out on his own volition, out of control, but he's being goaded into a fight -- and indeed baited to confront his human side and emotions. Being younger, I'd say Spock would have less experience handling that conflict 'in check' and would be a bit more volatile about it than he was in the TOS era.
MISSION:TREK's in-depth review of STAR TREK
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