There is no example of true Communism in this world at the moment. In fact, true Communism is (in my opinion) not possible. It would be lovely if it were possible, but it isn't.
Facism is possible, but not preferable.
Get it.
Good but not possible =/= Bad and possible.
You assume the political framework of China, Cuba and the USSR back in the day were Communism, but they weren't. They were failed attempts at Communism. The true Communism is what Karl Marx and Friedrich Engels came up with. Lenin's idea was to create a USSR largely based on that model (Leninism is very close to the Communism Marx and Engels created). Lenin died before it could be realised, and Stalin (indirectly) took over. He created Stalinism, which is not close to the Communism Marx and Engels created.
If Romney were to gain power, shot all senators and other politicians, and had his way with the US in doggy style, that is not a reflection of Capitalism, that's Romneyism.