Well, to be fair about Marx. Marx, first started out as a socialist and became more extreme and subsequently turned to communism.
That said, we have to remember when he lived, which was from 1818 to 1883. This era, was the "beginning" of the Industrial Age. There were no laws regarding child labor, no laws protecting the laborers; only newly created scrupulous businessmen that wanted to maximize profit, while paying their laborers as little as possible and even scamming them out of the very money the workers were paid, via company stores. This carried on into the early 20th century, however, in the west, workers gained a voice and laws have been enacted to protect children from working in sweatshops and mines, and unions forced companies to agree to workers terms. Federally, OSHA was created to improve working conditions and make it safer for the workers. Some mandatory income guarantees were put in place to also help workers.
Out of these changes, something new was created.....a "middle-class." This moved many out of poverty and improved their lives, significantly.
As for the poor, there will always be poor people. It doesn't matter where in the world you travel to, there are always poor and homeless individuals and I've been all over this planet seeing it.
So, when you see people trying to champion Karl Marx, just remember, they are looking at him through 19th century lenses, not the 21st century.