A mixed economy is a real thing; the US has a mixed economy. There are no purely capitalist or socialist systems. Cuba has a mixed economy of a sort as they allow for some private ownership of business. The US has combined a free market and the socialist principles of state ownership/planning (Obama care). Where it gets dicey is that the US has also pursued a policy of protecting certain private businesses (the 2007 crash is a good example) which is more fascist than capitalist/socialist. It's what the National Socialists did in Germany; private business/ownership supported by the state. Too Big To Fail is a fascist economic policy; Had the banks been put into receivership and then returned back to their shareholders once they were stable, that would be in accordance with the policy of a mixed economy.
Fascism is an economic system, as well as a political one. While both have elements in common, they are different. Stalin behaved like a fascist strongman politically, in that he was both General Secretary of the Communist Party of the Soviet Union and Chairman of the Council of Ministers of the Soviet Union, for life, and of course he had millions of Soviet citizens executed, assassinated, murdered or sent to gulags, for political crimes. Literally every crime or offense was a crime against the State and the Party so effectively the entire country was under the threat of death for causing an offense, real or imagined, by Stalin. That is why he was fascist strongman, as opposed to a socialist leader, like Mikhail Gorbachev, who had been elected by the Politburo.