I think you are misunderstanding the process of peer review. Yes, it was peer reviewed during the publication process. However, that does not mean there are no flaws in the analysis, or the conclusions drawn from the analysis in the paper. There are a lot of published papers in reputable journals that have been peer reviewed, but still haven’t been tested well enough to confirm the claims of the authors. In some cases the claims are just wrong. This process is iterative, and can take many years. We should never take any claims, no matter how compelling as gospel. Instead they should be met with varying levels of skepticism.