Fair enough. His explanation is still rather weak, though.
I can accept that Spock and Kirk didn't get along right away. Vulcans and humans often didn't. But, I simply don't buy this notion that he hadn't yet resolved his internal conflict between being part both.
It simply comes across as a totally unnecessary and unbelievable plot gimmick to explain something that never needed to be explained to begin with.
This type of emotional outburst would have been far better placed as a child or teen than as a Starfleet Officer who had already overcome most of the Vulcan rituals of purging emotions.