The creative brain, which is left and right working together, is what is needed for problem solving. it takes all things into consideration. One doesn't have to 'feel' empathy in order to realize that if one makes people's lives hard and miserable, they will at some point rebel.

If we all need empathy or compassion in order to act with kindness and ethics, we'd stand no chance whatsover.

By the way, INTJs often have very deep feelings, and they also have compassion. The fact that one is able to compartamentalize in order to sort out problems does not mean one doesn't have compassion towards others.