This whole argument is gaslighting on steroids. Kasparov, and many others who have taken the same tack, are deliberately ignoring the humanity of Bernie's statements and recasting them as praise for dictatorships.
He even explains what Bernie was talking about in the form of a rebuke:
"The people of Cuba and China survive, and sometimes thrive, despite their socialism and despite their brutal regimes, not because of them."
Yes, Garry, it's about the PEOPLE. You DO praise the prisoner of a concentration camp for their amazing art, because you praise the human being creating the art, not the filthy scum imprisoning them.