By living in a Marxist society, you are sacrificing your (and all those around you's) freedom. This IS immoral because without freedom you end lose free thought. And I believe it is better to die than to lack free thought. Without freedom life has no purpose; therefore, Marxism is inherently bad.
It requires everyone to think the same, have the same values, and share the same beliefs which is stifling and not consistent with the world most of us live in. Because of this it may work in small homogeneous groups for a while, but in a large diverse society it is oppressive and usually a vehicle for overthrowing a government or other group in power to replace them with another power that is often more cruel and ruthless than the group they replaced. Some say it was created by Karl Marx for this purpose, ie. To get the masses to do the work of a would be tyrant for free. Armies are expensive; delusional revolutionaries who are insanely devoted to an ideal are more loyal and much cheaper.
It requires that everyone think the same and have the same values and beliefs which is stifling and not reflective of the real world we live in. It is also usually a vehicle for overthrowing governments or other people in power to replace them with someone else who desires power and is usually even more ruthless and despising of human rights than those they replaced. Some say Karl Marx created it with that last purpose in mind, to get the masses to do what the would be tyrant cannot do alone.
The early human women were charged with the responsibility of the children, and other tasks back at camp DEALING WITH PEOPLE, thus they developed a better capacity for empathy. The rise of women in the advocacies in early America is proof of the concept of emphatic dominance and is also supported by William Marston
It isn't applicable to human society as some people will always put their own needs and status as priority rather than the wellbeing of society that Marxism advocates. Marxism is incompatible with the mindset of people, and requires almost impossible circumstances to work as it was intended to be and so is not bad in theory but impossible to accomplish.
Marxism is not inherently bad, it's a philosophy that attempts to explain why we do what we do. The core of Marxist philosophy to me is simple as that. Philosophers always juggle with the age long question, does the end justifies the means? A child steals bread for his starving family. Marx's explanation is human actions are based on economics instead of morality. That is one of the most brilliant argument I've came across.
In terms of being impractical. He theorizes that when human production becomes so efficient, when everyone can have the best the world can offer easily and cheaply, then we can all live in the John Lennon place where there's nothing that divides us. I can imagine where robots produce everything for us, and we have unlimited resources from space exploration... Why can't we reach that state?