¡Las Malvinas son Argentinas!
Why on Earth would a communist support a right wing fascist military dictatorship?
Geo-political hipsterdom. They are against a Western country so therefore are the good guys.
Ironically enough, the Soviet ambassador said something along the lines to the UK government : 'Go kick some Fascist ass'
And, of course, USSR abstained in the Security Council (along with China, Poland and Spain). The only country to vote with Argentina was Panama. Besides the US, France, and UK itself, resolution 502 was supported by Guyana (took a special lead on this - guess why
), Ireland, Jordan, Japan, Togo, Uganda and Zaire. Actually, UK had to work harder on the US than on Zaire!
Anti-colonialists, for god´s sake!