Shalaskasha
I tend to agree, but I have to absolutely disagree with the source you quote.
We see Spock physically assaulting persons twice in JJ Films, and we know from the Original Series Spock can and will use his fists in assaulting someone when his mental discipline fails him. We see him assault Kirk, and we see him assault McCoy, it two different episodes of the original series (both during times his emotional control was gone).
In the JJ Films, Spock uses his fists twice and both times are when his mental discipline has utterly failed him. Once not long after experiencing the death of not only his mother, but his entire world, when specifically taunted by Kirk, the other after Kirk dies and not to terribly long after melding with his former Captain (We saw in our world how far Spock would violate Federation and Starlet law over Pike) and experienced death from a human's perspective. And in this case was also taunted but by Khan this time.
Considering that "this" Spock has experienced far worse then prime universe's Spock (at least to the best of our knowledge), I think its absolutely believable to the character.