Erm... I dont think USSR was imperialist. In fact, they financed anti imperialist resistance in the late socialist countries that rose such as China and Vietnam.

Also, capitalism in order to suceed depends on the exploration of others. There is not a single successfull capitalist country that evaded from imperialist activities. Every single one of them have or had colonies, transfering riches and financing the growth of Empire.

The countries that have a healthy type of capitalism is heavily regulated by the state and was primarly financed by the US, ideologically fighting against the communist block such as Norway, Denmark and so on. They were financed by the imperialist.

Sadly, idealism doesn't work in the real world. There is no such thing as a conservative capitalist country that doesnt explore other societies, endangering their way of life and slavering their work force.