Yes, exercise is good for you regardless of weight. We should all do it.

But the idea that there is little evidence that obesity causes health issues is absurd. There's absolutely mountains of evidence, and we have very firm understandings of the mechanisms underlying many of these issues, too. Hell, just being bigger, even if it's all muscle mass, is bad for your heart.

The all-cause mortality curve is J shaped because many more of the people at 10% bf are there because of disease and not because they're shredded from a strict diet and a consistent exercise.

I've lost roughly 100lb of fat over the past 9 months. I have gotten back to lifting 5 days a week, but even before that with just losing weight my health markers improved significantly, I've felt better, aches and pains and discomforts have all but disappeared, etc. My stress, alienation, environmental contamination, etc. conditions are all the same, and I'm working just as much, if not more.