This procedure is very similar to self-murder (he kills his half). And it's very similar to betrayal (towards his mother).
Was it stated in the novel that Spock wanted to purge his human nature? Because in fact, Kolinahr is about Vulcan nature. Vulcans are naturally emotionnal, so they eliminate a Vulcan part of them by Kolinahr.
Spock left Starfleet to find his real place, to finally realised this place wasn't in Vulcan society, but in Starfleet and later in Diplomatic corps. It's not a betrayal if he felt more Vulcan than Human, he grew up in Vulcan society.
My Mom is Greek, but I never really considered myself as Greek and I don't see this a betrayal toward her.
I also suppose that most of people don't pass their whole adult life in Starfleet and that's pretty common to see resignations after ten or fifteen years.