I hear some people talk bad about capitalism why?

In theory, many ideologies look really good. But in practice, many of them perform much worse than expected. That's why so many people believed in Communism. But eventually they were disappointed, when Communism didn't work so well in practice. Perhaps people's disappointment with Capitalism is not yet as great as it was with Communism. But the potential for such disappointment is certainly there. Corruption and mismanagement by their leaders is what led to people's disappointment with Communism. And corruption among bank executives and government regulators who looked the other way is what's feeding people's disappointment with Capitalism now. When bank executives keep giving themselves millions and millions of dollars in bonuses, while the government keeps bailing them out with taxpayer money. Then most people who are suffering the consequences of such corruption are bound to feel disappointed. http://endthebailouts.com/2008/11/07/86-of-bailout-money-used-for-executive-bonuses/