There is nothing wrong with being kind and empathetic, but it’s the core of Marxism to attempt a scientific approach at socialism that is independent of particular proclivities or values among individuals. If your system requires people to be “virtuous” according to some arbitrary definition of the term (as all definitions of the term would be), your system will live only on luck and die very quickly.

There are elements of “human nature” which are important to Marx, but they are more fundamental and generalizable, like how humans transform their environment to suit their desires, etc. Ideology is usually relevant on a sociological level, e.g. “In all ages, the ruling ideology is the ideology of the ruling class.”

Personally being kind and empathetic is a good thing, in fact a very good thing, so long as you know where it can lead you astray. This is something that the film “Young Marx” deals with excellently, for example in this scene.

then Marx’s analysis does not rely on saying its human nature to be evil whatever, so the same way it does not also need to rely on saying its human nature ANYTHING

That’s right. To put it briefly, according to the Marxist world outlook, there is no such thing as universal human nature; the way that humans act is historically contingent. If there is such a thing as human nature, it has class characteristics, as well. People in one epoch will tend to act in one way, while people in a different epoch will act in another way. People in capitalism appear to be universally greedy in capitalism but why wouldn’t they be greedy? The system is set up in such a way that if you’re not greedy, you might starve and become homeless.

At the same time, the greediest people are the capitalists and they do two things particularly well: 1. projecting their own personalities onto everyone else, and 2. using news and entertainment media to convince the rest of us that they’re right. Movies like 1900 and I, Daniel Blake raise a challenge to this narrative.

Whatever else all this means, I’m well on board with ‘empathy/love and solidarity’. They certainly make organising easier. And appealing to these traits in most people can make it easier to erode some reactionary views.

The way I see it, there’s 3 ways to interpret human interactions. Very generalized and simplistic overview:

• Realists believe that humans act on self-interest and the pursuit of power/wealth/dominance. This is essentially the human-nature-is-bad camp. Realists believe that world peace and prosperity can be achieved if there’s a balance of powers, where if one individual attempts to dominate the others, the others will band together to stop the dominator, as it is in their self-interest. Example: the way Europeans carved the world after the Napoleonic Wars. Also, the Cold War.

• Idealists believe that humans act on mutual interests based on ethics and morality. This is the human-nature-is-good camp. Idealists believe that world peace and prosperity can be achieved if everyone is an idealist and preferably liberal. Example: US foreign policy focused on enforcing US ideology/hegemony all over the world through economic and military power.

These two worldviews have dominated politics for most of history.

• (Historical) Materialists (Marxists are part of this group) reject both of the above worldviews and instead believe that humans act based on multiple factors, that can be condensed into economic and material conditions. These conditions define class. Dominant classes (or nations) will always exploit the subservient classes (or nations) and define society to reinforce their dominance (i.e. their ownership of the economy), which Marxists are opposed to. Marxists believe that world peace can be achieved if classes are eliminated, and the way to eliminate them is to ensure that the economy is equally shared by all individuals and benefits all individuals equally. Marxists don’t believe that human nature is that important to consider, as humans will be forced to act in certain ways according to their circumstances.