These countries are not socialist, they are communist. Communism is when the government has complete control of the economy of the country and often devolves into just a generally totalitarian rule. In communist countries there is often no such thing as personal property. Socialism is where the government regulates the economy, but people still have a say in what they buy and sell. Although America is very much a capitalist country, we do have some socialist elements such as unemployment and disability checks, social security, and laws prohibiting monopolies (ex: CNN couldn’t legally buy all the other news networks).
TLDR: socialism and communism are two different things