I think it’s a bit extreme to go from “our bodies likely have some amount of tolerance for a hazard that has existed and been a fundamental and inescapable part

I think it’s a bit extreme to go from “our bodies likely have some amount of tolerance for a hazard that has existed and been a fundamental and inescapable part of life since before there even was life” to “the body must surely have a way to deal with this toxic element that isn’t common in the environments where our species evolved”. I’d go so far as to say you might be ignoring some important differences between the two!