Ofc they are. Capitalism (and socialism in certain regions, ofc) did significantly reduce world poverty in the 20th century, that is an undeniable fact. What neolibs fail to recognize are two fundamental pieces of context:
1. The vast majority of these third-world countries were feudal or semi-feudal in economic structure, so their massive increase in virtually every aspect of life is still in line with Marxist history.
2. That the capitalism of today, the capitalism has ushered in this economic prosperity, is in a far more statist, centrally-planned form than at any previous point in human history. By defending this increase in human life as "the prosperity of capitalism", what they really have to accept is that the capitalism they praise is a Keynesian, relatively progressive capitalism that they almost certainly would've called "descending to socialism" had they been born thirty years earlier. Capitalist ideology can't seem to reconcile the fact that, in order for capitalism to continue its dominance, it needs to make ever-expanding concessions to the state and to the general welfare. Obviously, these concessions are made grudgingly and with ulterior motives, but the smart capitalists know how to accommodate this change, while the idiotic, ideological capitalists cling to their status quo and inevitably find themselves trampled.
3. That a large portion of the world population has either lived under or is still living under socialism, and that this coincides with the boom in prosperity. Beyond the fact that countries in the Soviet sphere benefited from this growth just as well as capitalist countries, in the present era, nations like Vietnam, Cuba, Laos, and China (dispute if these countries are socialist if you want, but it's undeniable that they are NOT the "laissez-faire" capitalism that neoliberals desire) have seen comparable growth, with China, Laos, and Vietnam actually seeing tremendous growth compared to the average neoliberal nation.
So, while the info presented is correct, it is missing fundamental context that, when applied, actually paints a picture in favor of socialism and historical materialism, not against it.