Why do so many humans struggle with the concept of compassion?

[Black Dragon]

In a nutshell, RitaJC is right about the fear thing, at least for 90% of what motivates lack of compassion being fear in some form or other. Here's some of the more specific manifestations of that idea that I think contribute:

First you've got the obvious ones like Tribalism(as Diana mentioned), which ties into racism, nationalism, toxic politics, and basically seeing people as "the other". Another obvious one is humanity's general level of treatment toward our environment and animals, and those plundering and abusive behaviors stem from fear of lack of abundance and the feeling of needing to compete for resources, and from the concept of hierarchy and arrogance that man is superior to his environment and lower density life forms.

The hierarchy thing ties into the concepts of conformity and authority. "Society" as a construct is generally not very compassionate. The people that tend to be successful in this setting are also not very compassionate. Most of the "rest of us" are confused and/or apathetic, and conform easily. This manifests in a "survival of the fittest", or "might makes right" ideology.

A really big a lot of people don't consider is weariness/fatigue/burnout-just the drain and drag of life and the system. Think of your decent every day person that's more or less in the sinkhole with some flashes of insight, or even consider wanderers, because it happens to us too. Think of all the stress of daily life on this planet and how much time and energy a lot of us spend just keeping up with the demands of red ray physical existence and yellow ray society, not to mention how much time and energy many people spend serving other people and institutions that don't care or have compassion for them.

Somebody who busts their butt at some job they don't enjoy where nobody cares if they drop dead the next day, where their boss will throw them under the bus for the smallest crap if the situation calls for it, probably wants to spend most of their free time attending to their own needs-mostly "rest, distraction, and anonymity", but also whatever kind of self-actualization or fulfillment of their own highest excitement they are able to do with their limited time. That leaves very little time and energy for being extra compassionate of the needs of others, and when the choice is made to serve others while the "tank is on empty" like this, it can feel like a draining sacrifice rather than and effortless gift. Too much of that and a person just kinda zombifies-its not that they don't want to be compassionate, their 3d mortal supply of compassion has just been fully drained.