"Observational study" does not mean "bad science". There are good and bad observational studies, and without reading the paper, you can't know which one this is

"Observational study" does not mean "bad science". There are good and bad observational studies, and without reading the paper, you can't know which one this is. Moreover, your assertion that only random trials can be controlled is just completely wrong - there are plenty of ways to do controlled studies on observational data. You're engaged in the scientific version of the middlebrow dismissal. In health sciences, a lot of good work starts as well-controlled observational science. In fact, for a question like "does sauna use lead to a reduced risk of dementia over a human lifetime?", pretty much the only way you're ever getting the funding to do an "RCT" is to start with lots of observational evidence.