Don't get me wrong, there are a fuck ton of unhealthy people in the US, but weight isn't the end all be all. I've been "overweight" since I was 15, for the last 14 years now. I'm also 11% bodyfat and very very athletic. Weight and BMI are bad metrics.
Garbage in, garbage out. If you do a complex mathematical equation, and one of the values is garbage, the output is also garbage.
I don’t doubt that this generation is more overweight, but using flawed data and pointing at the lack of data proving the flawed data matters, doesn’t make it good data.
BMI isn’t always a good metric for an individual, but it is a great metric for populations studies when there are other controls. It can be used to analyze trends, but no one person should feel like it means much for them in particular.