Sarek was no pacifist. As far back as "Journey to Babel," Spock stated that his father was perfectly capable of killing in cold blood if he had a logical reason to do so.
As for how the Vulcan's insular ways and open disdain for more emotional races meshes with IDIC . . . well, they're hardly the only culture that has some built-in contradictions. Indeed, one can argue that it makes the Vulcans more believable if they have conflicting values and priorities--and don't always live up to their ideals. ("Ideals" are goals to aspire to, not something everybody lives by all the time.)
Killing somebody in self-defense (or even only in
percieved self defense), and still being a pacifist, aren't mutually excluse. Sarek was a
strong pacifist, who always advocated for a diplomatic solution, way above his simple commitment to his job.
And, as I've harped on before, the Vulcans have NEVER been presented as role models. Hell, the first full Vulcan we ever met, T'Pring, plotted to get Kirk or Spock killed just to get out of an arranged marriage. And Sarek was first introduced to us as a murder suspect! TOS portrayed them as a shifty bunch from Day One . ..
Considering Spock(!) was a role model, and for a long time the only Vulcan we know, yes, we can say Vulcans
were somewhat role-models. Spock was never portrayed as "out-of-the-ordinary", or "the-only-not-racist-Vulcan".In fact, he represented a lot of "Vulcan ideas" to the viewers, like IDIC, and showed the general benefits (and sometimes flaws) of a purely logical apporach to behaviour.
T'Pring plotted her way out of an arranged marriage. Hardly something "truly despicable racist". And in case you didn't notice: Part of the Sarek-as-murder-suspect mystery was
why he would do something like that, which
really isn't in his nature.
You're REALLY fucking overstepping your boundaries of "they're all a shifty bunch" here. If you'd talk that way about any other speices that is not fictional, it would be hella' racist comment. As it was, Vulcans were just portrayed as "different", following logic instead of emotions. But with still being individuals with different personal conflicts or interests. Hardly something to chastizie them for.
IMO having flawed individuals is way more realistic than a "perfect logical society", which would be the other extreme compared to your "a bunch of racist assholes". Generalizising entire species is something that really shoudln't be done, and that Star Trek even
tought us not to do in the past.