It's easy to perceive an INTP that way but generally I don't think so. I've been called callous or its ilk and the complete opposite.
A strength of not being overly emotional is that when conversation comes up with a person that is struggling with something you can talk to them and calm them while avoiding get caught up in the emotion. Kiersey in his book, "Please Understand Me II", talks about the Rational/Idealist couple and says the Idealist is prone to tempests of emotion that can be debillitating and that the Rational can serve an anchor that gives them safe respite and calm. Conversely the Idealist helps draw out some of the emotional side of the Rational which helps to invigorate them.