Capitalism shows that people that are more skilled get more recognition for it, for example, a doctor makes more than a cashier. It's the same as saying that when you were in school, you did the entire project and worked hard on it, and the person next to you didn't and they got the same score. You should get a higher score because you did better, in communism this doesn't work. Communism doesn't work because one, if you don't own it, why should you maintain it? And socialism doesn't work because it takes money people earned and gives it to the poor that did nothing to earn it.
Capitalism is fair. Would it be fair that everyone earns the same amount of money, but one works harder? No, right? Even if a country would be ruled by communism, there still will be poor and rich. It will always be this way. Therefore it can be said that capitalism is better than communism
All the arguments against capitalism are either targeted at crony capitalism, facilitated by big government, or against the unchangeable nature of the world and humanity. The rest are just completely nonsensical. People will complain about rich people controlling the government. This is true: men with big pockets will try to take advantage of government for their own ends. However, this can only happen when government is big enough. A small government which only serves to enforce the law and defend national security is less capable of being corrupted. However, powerful government organs, like the IRS and the Fed (un-democratic and unelected) open the door for cronyism, as do powerful elected officials with lots of power. Complaining about inequality is to complain about human nature itself. There will always be inequality as long as two people are left on the planet.