Since you took the time to read the results section, maybe you should have also read the discussion and conclusion sections as well. Yes, they did attain that figure after adjusting for confounding variables, but keep in mind this is an observational study. By the authors' own admission, residual confounding effects are still a weakness of this study. Simply controlling for BMI in an analysis doesn't negate it's role in the research, as the researchers themselves stated in the conclusion:

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These risk differences were likely partly due to their lower BMI

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The researchers didn't jump to these conclusions so why have you? There are many factors beyond the numbers that you need to take in to account. Maybe you need to brush up on your knowledge of research methods.