Trust. Russia and China lie through their teeth on everything and anything. It's irrelevant whether or not they are lying in this particular instance: they cannot be trusted.
Of course, in Mother Russia it is widely believed that everyone lies more or less, and those looking to expose "the truth" generally live dangerously, often with tragic results.
You think russia and china lie because of propaganda. Their citizens believe we lie because of propaganda.
Whether one views another country favorably relies entirely on propaganda.
But given how these western countries handled covid, and the fact that China has a history of fighting viruses like it- I'd rather trust a Chinese vaccine over an American one, all else being equal.
Western governments are no doubt better for their own citizens than say Russia or China, but we outsiders have absolutely no reason to trust one government over the others. Russia's vaccine has only passed phase 2- now that's a good point, "Trust" absolutely isn't.
That doesn't necessarily mean it was justified, but I do think it's important to note the difference.