Karl Marx is known for two things, having a great beard and creating the theory of Marxism. While one is a great achievement that should be commended the other was a rather out of reach idea that led to many of the worst and most oppressive government regimes in history. Of course our bearded friend didn't mean for it to end up that way but like many good willed, yet misguided ideas, they become a nightmare…much like the idea of using Cylons (robots) as a form of labor in Battlestar Galactica. The outcome can be catastrophic.
To understand why Marxism led to these corrupt and oppressive regimes you have to look at the definition. Now this is where many leftists will say "Nuh uh, you don't know what it means" since that is usually their defense but this IS the definition and it explains so much. Let's use the always-trusted Merriam-Webster. "Marxism: the political, economic, and social principles and policies advocated by Marx; especially : a theory and practice of socialism including the labor theory of value, dialectical materialism, the class struggle, and dictatorship of the proletariat until the establishment of a classless society. A classless society." That right there says it all. A society in which there are no classes, everyone is equal. No poor people? That sounds just as amazing and just as believable as living in the Peppermint Forest from Candy Land. It is almost impossible to have a classless society where nobody answers to anybody else. The moment you let the government redistribute wealth and control production and commerce you just set up government officials as the ruling class. It leads to them being very rich and the regular workingman being very poor. It's why people in North Korea are starving and resort to eating grass. It's why people from Cuba will risk their lives on rickety boats to get to Florida, no matter what Michael "Ton-O-Chins" Moore says about their healthcare system. They aren't coming because they want to check out the lines at Disney World.
Now, I've heard people make the argument that the original Native Americans had a system of sharing and giving to the common cause of the tribe but those were basically large extended families with a hunter/gatherer system and bartering. These weren't nations made up of hundreds of millions of people that drive cars and play Xbox. Who is going to make your Xbox under a classless society? Someone making that Xbox is working for a boss and they are working for someone else. If everyone was set at an equal income, who is going to decide to create these products and put all the effort into them? There is no incentive for it. If you are trading rabbit furs for someone's corn and squash crop you are basically equals but if you want to have a society with massive production then someone is going to be working for someone else, plain and simple. A classless society on a scale of a nation like America is a complete fantasy.
It is impossible for the government to make people equal. The only person that can raise someone up out of his or her current station is the individual. No matter how much the government assists or gives them handouts it is ultimately up the individual to do something. A government can't make all of its people rich but it sure as hell can make many of them poor. The examples I stated above along with Communist China and the USSR are great examples. The average person lived in squalor while the government officials lived like nobility, the very opposite of a classless society. The private sector has its issues with corruption but can you think of anybody more corrupt than a politician? Giving them too much power is like giving a fox the key to the henhouse or your Snapchat access to Anthony Weiner. You end up with socialist nations such as Venezuela under Hugo Chavez that through government owned media, shut down his critics and political opponents. People will praise socialism in European nations, but remember that these nations are still kept in check by not having complete state ownership of everything and while they're touted as great by those on the left they still are not even close to being classless societies. They still have their poor and their very rich.
Basically our good buddy Karl was a dreamer. He wanted everybody to be equal but he didn't understand human nature. He probably should have just been satisfied with growing and maintaining a great beard and left the political theories and thought to others because you're more likely to be ruled by Lord Licorice than live in a classless society.