Yes. That's why you do a serial killer in a storytelling narrative. Either they are evil outright with no reason, or you get a profile of how messed up they are and how warped they are. Usually that is sprinkled throughout the story, even before you know they are the killer. We know that he suffered a trauma, but we don't get anything other than "well, it must have affected him". I mean, I think it would have been better if his only word and explanation on the matter was not "Because logic demanded it". Because he does not come off as deranged or distrubed. He comes off as calculating for something he fully understands, without a reason to hold back anymore because "emotional humanoids are bad, as all we Vulcans know, so I will no longer be polite as to tolerate them". And I highlight tolerate because, taken in conjunction with other Vulcan appearances on DS9, it feels like their take is that the Vulcans never like or get along well with others. They just put up with non-Vulcans, with regular snobby, passive aggressive remarks to show their true disdain.