Capitalism is a good system to allocate scarce resources, and it has created wealth for a lot of people, but raw, unfettered capitalism is a disaster for the average person. For a just society to work with our current level of technology capitalism and free markets are an important part of a mix of policies that should include socialist elements to ensure everyone has at least a minimally satisfying life.
Believing there is only one true way to run a society, for example dog eat dog capitalism, or strict communism, generally leads to disaster. A mix of elements that has been shown to produce the best result for the most people should be used. And that best mix has been shown to be a mixed economy like those in northern Europe, France, and somewhat in Canada. The more laissez faire capitalism of the USA is a failure compared to these countries when you look at objective yard sticks like life expectancy, income disparity, social mobility, average salaries, access to medical care, education, etc...
Economic dogma is just as bad as religious dogma.