While I wouldn't agree with this, I might not find it an absurd proposition if global capitalism had only ever had an effect on white people in the imperial core and that was all we were allowed to consider about it-- and this is very much how capitalism tends to be considered in its effects by media in imperialist countries-- but that's not the world we live in. So instead I must regard your statement as ill-considered in the extreme. Everything wrong with capitalism is compartmentalized as some particular social problem or another while any blemish on a socialist country is treated as fundamental to Marxism. We'll decry "gulags!" while the United States has by far the largest proportion of prisoners in the world. We'll snark about "bread lines" while our people starve. We'll laugh about thousands of identical soviet apartments while our people live on streets and (if lucky!) in tents. But more important than that is that capitalism is fundamentally and unavoidably about the exploitation of its working class and functions by keeping the mass of people precarious and (rightfully) terrorized of falling to a lower status and thereby having to accept more brutal exploitation, losing one's home, or being disposed of when a medical treatment is too expensive or a cop decides to perform an impromptu execution.
The bit about compartmentalising in capitalism and socialist failures as inherent to Marxism sounds to me like some sort of digressive waffle. It's not that capitalism is inherently ace and socialism inherently shit or vice versa, it's just the reality out there was that the Eastern Bloc and China fucking sucked. And irrespective of whether this is some sort of inherent problem of socialism or not, they were unquestionably horrible places at a deep institutional level, and the idea that socialism might be doable in some other less patently abusive fashion in no way excuses the barbarity and harm those places inflicted on their own people (and others).
Do you want to tell me that the working classes
weren't exploited in the USSR and China? Do you really think the wealth of the nation was truly flowing to the workers, or do you think it was being wasted in inefficiency or sucked up and squandered by an elite for other purposes - just in this case, a governmental elite rather a capitalist one? DO you think the workers really had any significant say in their lives, and government policy?
It is surely a form of exploitation to view one's people as a series of replaceable cogs in a giant machine, where the only thing that matters is the machine, and if you grind up millions of your own people, that's all fine. Capitalism does this, but so did the Communist nations. They didn't love and respect any individual in their country as persons, they're all just fodder for the Great Plan. That's a lot of why they were convulsed by events where millions died - because it was small loss in the name of whatever ambitions socialist dictators had. If you think it was not exploitation, you are fooling yourself. Likewise if you think they did not live in fear and coercion - albeit via insidious security services, corruption, shitty justice systems, daring to speak what was ideologically impure and so on rather than economic insecurity - you are fooling yourself.