It's not that different (it is different, sure, but not that much) from how people who look at capitalism and only think of rich countries, ignoring the ample supply of capitalist countries with completely failed economies. Of course there is also a bit of survivorship bias here, because failed economies are much more likely to try out communism than flourishing ones. After the revolution, one easily blames communism for economic failure that actually happened before.

I'm not saying that we should all turn commie, but just looking at the richest country and acknowledging that they are not communist paints a very incomplete picture. (By that measure, we might also determine that we should ditch democracy, because look at how wealthy a few selected monarchies are!)