I suppose Sarek telling Spock he married Amanda out of love is a worrying sign, too?
There was never a moment in TWOK with the emotional impact of the destruction of Vulcan and six billion of its people. I'd think even a Vulcan should be allowed to at least momentarily go apeshit over something like that. Same with Khan in STID, Spock believed he had killed Kirk. Remember, in ST09, Sarek set it up early in the movie when he told young Spock (and the audience) that emotions run deep in their species, deeper than even in humans. Every Vulcan is a volcano ready to erupt without the serenity logic gives them. But that doesn't even work all of the time.
The very reasons Vulcan society is so uptight and rigid is to protect the dogma of emotional suppression and the very reason this dogma exists is that those volcanoes have to remain silent lest Vulcan society tears itself apart. So telling your son to not suppress his anger after his mother died is totally reckless.
Now I don't mind that the movie depicts a younger Spock who does go apeshit from time to time. Bring it on! But if the texture of the movie applauds him going apeshit instead of viewing it critically (like during the mind-rape scene in TUC) this is questionable.
My favourite movies are TUC and FC precisely because the protagonists make mistakes. But neither movie applauds them for making mistakes.
I don't see either movie applauding Spock's actions in any fashion. If he is being cheered on purely because he is the hero, then I suppose that I should cheer him on for beating on Kirk or not wanting Kirk to attempt to negotiate peace with Nero.
But, for me, I don't. I recognize it as a layering effect of Spock's emotional state.
I don't think Sarek is telling Spock to go crazy, but to acknowledge his human side. The rest of the context of conversation is one about Spock finding the balance between is two sides, not just "embrace your emotions and don't care about the consequences."
Again, people's interpretations may vary, but I don't see the film casting a judgement call on Spock's actions, besides the fact that he is the hero. I think, when viewed critically, it lets the viewer consider the whole of the character, and view each scene within the context of the larger whole.