The type of murderer who just completely flips out isn't described as "cold and calculating" but we might describe a strategic killer that way. However, that comparison just means the strategic one is thinking more - not necessarily that the thinking being done is more intelligent. It might only imply that the strategic one isn't flying off the handle in response to emotion.

Try this scenario:

There's a murder who wants to kill a certain victim. The murderer watches the victim for a while to discover their commuting habits. They make a plan and purchase supplies. After a few weeks of planning, the murderer waits in the bushes, possessing everything necessary to kill their victim - formaldehyde for a snare, handcuffs for restraints, a knife, and a first aid kit in case the victim hurts them in a struggle. They wait for an hour until the victim is in exactly the right spot, and then they pounce with the formaldehyde. The murder handcuffs the victim and takes them to a different location where nobody can see. Then the murderer kills the victim.

Is this murderer cold and calculating?

Did the murderer use more strategy than the average person might use on a camping trip that involves hunting?

I think the answer to that is "no", so the meaning is potentially more like "cold enough to calculate" not "cold but intelligent".

Also, "people don't care how much you know until they know how much you care". If people see you as malicious but weak, say a child who fights with the other kids, they're likely to write you off as an annoyance and ignore you.

However, if they see you as malicious but strong, a fully grown person who is a rapist we'll say, then one is seen as a threat and people will pull out all the stops to get rid of you. A serial rapist gets news coverage. People stay indoors to avoid them. Police put in extra effort.

How often have there been news reports of a child bully wandering the sidewalks, urging you to protect your children? Probably never. That would just make people laugh. But I've seen rapists on the news plenty of times.

I think LessWrong would be better off with a label that means something more along the lines of "harmless nerds" or "intelligent people who care about the world".

I'm pretty sure cold and calculating means something more like "monstrous".