The reason why the USSR was trumpeted as socialist was that it suited both sides' propaganda to do so. For the Americans, to vilify socialism, and for the Russians to give their rule the appearance of genuine socialism. When both of the major propoganda systems in the world agree on something it's bound to become a popular conception.
But let us not also forget that hundreds of millions starved in non-communist India, which suffered terrible famines up to 1948.
South and Central America was a horror chamber throughout the 1950's-1980's under violent brutal capitalist dictatorships supported by the USA. Many Asian countries too.
The rise of communism in China, although violent and of the state-socialist kind, also brought hundreds of millions out of poverty.