I didn't get the impression that he was terribly angry about it in the purest sense of the word; just the delivery of Sahara-dry humor that I think oftentimes gets misunderstood. I mean, here's what he said:
I'm sad... So they name a moon Kerebus because there's already a Cerebus asteroid but a mythological planet knocks out Vulcan?... Star Trek fans have had it rough. First JJ (Abrams) blows up Vulcan and now SETI finds a loophole to deny it from coming back!... I think they used us for promotional purposes! They're probably Star Wars fans!
That's not anger. That's pure Shatner snark.