Perhaps you haven't been paying attention to the skyrocketing prices of fuel, food, and healthcare... Or did you just think all those people just above the poverty line disappear when the livable income floor gets hydraulically jacked up?
They are not all in one place, and their death certificate doesn't say "politics" on it. They are in cemeteries all over the country and died of many different immediate causes.
I think they mean, the USA (or capitalism in general) is currently killing millions of our own people.
We know how many people communism killed, but has anyone done the same math on capitalism? Maybe they're both very bad, and we have to find a third way.