Is rational economics heartless?

To be rational to use reason. To be heartless is to lack compassion or morals/ethics, something like a sociopath.
EconLog have a good article on this very subject.

This is more of a philosophical question. Is being rational, using the facility of reason or your mind mean you lack compassion?

That is the real kicker, Adam Smith nailed this centuries ago. You can be completely self directed in your production and consumption and people still benefit more, than if you allowed someone else to determine or direct your actions. The invisible hand!!

This is the difference between a free, bottom-up market (capitalism) and a directed top-down market (statist = socialism, communist, nazism, rabid environmentism).

I suggest reading some Julian L Simon (Ultimate Resource) or Ayn Rand, or even "7 effective habits". The human mind is the powerhouse, the fount of capitalism.

As my older brother used to say when we were whining and complaining, "Get a grip (with reality)" i.e. no amount of whining and complaining is going to change your situation. You have to think and act.

Have Fun