I’m not surprised anymore when I see that writers for Yahoo! Style have no idea how to make a possessive out of a plural noun. It happens nearly every day:
So, the writer and editor didn’t know that athletes’s makes no sense (they should have written athletes’). What surprises me is the fact that they thought they needed to make it clear that it was physical bodies, and not imaginary bodies, that are the focus of “microagressions” (they should have written microaggressions).