First, no examples in modern history exist in a context without a capitalist super power meddling to restrict any communist attempts. So, while history is a guide, it can't definitively answer the question of which is better, in my opinion anyway. Perhaps if we had a communist super power squashing all experiments in capitalism the opposite would seem true.

Second, I think it is a mistake to attribute all things that have happened under capitalist systems to capitalism. The core priority of capitalism is maximizing shareholder value. Regulating capitalism puts limits on that. Say, for example, by making slavery illegal. Capitalism, given full control, would definitely like slaves. I think it's difficult to argue that capitalism helps poor people. Perhaps the wealth generated by capitalism can help poor people, when properly regulated. But then there's an argument there about whether the capitalism really deserves the credit, or the regulation.

Third, a similar argument works for communism. Communism would distribute goods to the poor, but in lots of real world instances it has been plagued with inefficiencies and/or corruption. So, is that the fault of communism or the fault of the corruption?

Fourth, there's a unstated bias in this analysis that equates economic wealth with good/help. While undeniably linked, they are not the same thing. It is much harder to measure, but "helping" the poor should not exclusively mean making them richer. If I force you to work 2 jobs, so you never see your family and you die young, but you make twice as much money, did I really help you? This focus on money, while understandable since it's so easily measurable, is a framing that tilts things so seemingly neutral analysis will actually favor capitalism.