Congratulations, you picked on the one outcome that the authors of the genetics article (if you had even read it, you would have seen) said "Whereas most obesity-disease associations were largely similar, adjusting for smoking status resulted in diminished magnitudes of effect for COPD and lung cancer, suggesting potential mediation." In other words, the COPD association was potentially mediated by smoking but the other associations "were largely similar". This supports the conclusion that obesity is causally associated with a range of diseases even if COPD isn't one of them. Extremely lazy argumentation on your part, and still denying the science.