I really, really don't get your point. BMI might not be flawless as a measurement (there are better ones), but obesity is an established medical diagnosis with well known concrete negative health effects with tons of research throughout the decades, so I'm not sure what "rhetoric" you're referring to? Yes, it's a complex condition influenced by many factors, including genetic and socioeconomic ones, but regardless of what combination of factors causes it, it doesn't change the fact that an obese person is, well, obese. It's a medical term, not some arbitrary label assigned to someone in order to discriminate or create stigma. I think the article is just trying to spin the latest research on obesity and covid-19 into some sort of a social issue, which in my opinion is a very weird thing to do here.