That quote says “killing people a lot longer” not “more than”.
I’m not a sociologist, but how would you measure the number of deaths caused by racism in a fair and unbiased way? I assume it’s something along the lines of the difference between disability-adjusted life expectancy of different ethnic groups, but even then you have a question of are things like poverty and education levels confounding variables or examples of systemic racism?
Likewise, are the healthy life years lost to genetic disorders like sickle-cell anaemia the fault of society for not treating them or the fault of the genes for being adapted to (in this case) malaria when there isn’t any malaria around to protect against?
And even if everyone agrees on the same answer to the above, the fact that racism hasn’t been constant over time makes it unclear what you are integrating over and when you are integrating between — The absolute racism since the Declaration of Independence or the estimated difference between actual history and a hypothetical counterfactual that nothing changed since the race-segregated toilets were drawn into the original design of the Pentagon?
I mean, if you count all the racism in post-Columbus Northern American history, you’d also have to count the literal genocide of how many native Americans tribes, and I’d also argue the slaves. I can even see a way the non-slave deaths during the American Civil War could count.
What I can’t see is a way to be totally clear in advance what the question is even supposed to answer. They’d all be true, but they’d mean different things. If I had to guess, these are all big numbers, but they vary by more than two orders of magnitude.
Like the saying says: lies, damned lies, and statistics.