Being overweight increases the risk of developing quality of life reducing conditions and that is bad (it’s not being overweight itself that is bad). This is the case even if it doesn’t lead directly to dying. I would be careful about pushing the narrative that being overweight but not obese is just fine just because it won’t significantly increase your chance of straight up dying. Type 2 diabetes is a treatable condition so might not lead to a significant increase in deaths, but not exactly something you would want to develop if you can avoid it. And your chance of developing just that does increase if you are overweight even if you are not obese.
I'd like to emphasize the "might not": The impression I get from all these studies (I've seen them pop up pretty regularly for as long as I've been paying attention, nearly two decades) is that the border is actually wrong, that going from "normal" to "overweight" should be increased slightly from 25 to 27 or so. We're probably getting mixed signals in the "overweight" classification because "okay" and "bad" levels are being combined.
