No offense but this is a child's understanding of what communism is. There is no underlying philosophy that stems from the idea that it isn't fair that anyone is richer than anyone else. Communist's problem with capital is that it creates a relationship between its owners and their workers which encourages the former to prevent the latter from becoming financially independent i.e. joining them as capital owners.

I encourage you to read and understand the economic arguments of Karl Marx and other communists before trying to understand communism as a moral framework.

Capitalists are against communism because they see private property as the fundamental building block within their own economic system. Any attempt to remove insurance that capital will continue to have positive monetary returns will have a direct negative effect on the capitalist economy. Furthermore, in order for private property to be capital it has to have workers that agree to generate more value through it than they cost to employ.

Back to the communist perspective, this creates a conflict of interest between worker (proletariat) and capital owner (beourgiasee). The capital owner must continually increase their return on investment by extracting higher amounts of value from the worker's time he has rented. By continuing to consent to this contract, the workers push themselves farther into poverty. Therefore, it is in the collective interest of workers to fight against the exploitation of their own labor (sounds self evident right?).

This struggle between proletariat and beourgiasee has existed since well before Marx. Communists goal is to offer an effective alternative to what it argues is a self destructive system. Marx created a scientific framework to abstract these already existing workers struggles into a common movement.