Haha yes, definitely suspicious. There must have been other factors at play because if it brought them such pain to feel another die, they'd never have gone to the verge of extinguishing their own species.

Also, I don't understand how I felt the death of a bunch of Vulcans translates to I know that not even the computer was expecting that.

Well, I suppose you could handwave it as 'the Vulcan science officer had done all sensor sweeps and reading and stuff and even from the sum total of the computer output, it was completely unexpected'.

Or, which I prefer: there's something about a Vulcan's relationship with his computer that Spock hasn't been telling us. :P

The thing about TOS is that it was largely episodic so the whole thing has less cohesion than one might wish but on the other hand, it gives us lots of leeyway in interpretation and hours of fun trying to come up with explanations for some of the sillier things.