Sure capitalism kills people, but not nearly the same order of magnitude. The worse cases of unbridled capitlaism killed far less than any one of worse cases of communism where we're talking to the tune of hundreds of millions. Then capitalism helped spawned things like the "green revolution" that prevented mass starvation across the globe since then.
The scientific consensus is that within a century unbridled capitalism will end up killing an order of magnitude more people than any other system ever did.
It’s like saying that Math kills people because Math is used to build bombs. Capitalism is an economic system, not a social system. There are human beings in charge of corporations doing the killing, polluting, and so on. Those individuals are responsible.
Except that fossil fuels aren't limited to capitalist countries. Even then accounting future potential deaths to an economic system is a bit meaningless compared to prior concrete and repeated history.
Much less there's no way we can accurately predict the death toll of something a century out -- in the 1960-70's it was "obvious" there would be billions dying of starvation. We could crack fusion power in a decade and use direct CO2 capture to reverse CO2 levels to pre-1850's level.
