This isn't the first time the delivery of the dialogue in this scene has been bashed. Personally, I think if the guy on the intercom had been emotional it would have come across as too melodramatic or even campy, especially since it's only a voice and you never see an actor's face. As it played out, it kind of makes sense. People, when faced with traumatic situations like that, often emotionally shut down for self-protection. They don't always fall apart and start balling in grief.
How the heck was the transporter accident Kirk's fault? He wasn't manning either station when the transport started. He was down in engineering with Scotty when they got the alert about it. He didn't even give the order to transport at that moment. The most you can lay at Kirk's feet is that he gave the order for the Enterprise to be ready in 12 hours, which may have led to some undue haste and carelessness on someone's part.