The Poles asked for their troops back when they were forming a USSR-based army and were told that thousands had mysteriously escaped. Then when asked for an official investigation, the Soviets broke ties with the Polish government in exile and made their own.
The Soviets themselves later admitted it was the NKVD. Are you defending the USSR from its own slander?
As did the Soviets, what are we even talking about here?? You just respond to each criticism with "they needed to do it and what about the US", ignoring the multitude of other actions they could have taken if their priorities matched your claims.
Which they did once they had Soviet support. They almost certainly would have received the same support if they joined them in 1939.
It was official USSR foreign policy that the communist revolution should spread to workers of the world in all countries. Regardless of the detriments or merits of that, you can't ignore it when examining their foreign relations. Of course they got a different treatment...
They absolutely did not! One of the main factors that broke down the USSR-German relationship was a refusal to reciprocate military technology and materials.