You're not wrong. Almost all observational studies could be subject to confounders which if true would invalidate their claimed results. But you seem to be su

You're not wrong. Almost all observational studies could be subject to confounders which if true would invalidate their claimed results. But you seem to be suggesting that just because science is hard we should accept the results of all these flawed studies at face value without further questioning. The better conclusion is that we should be skeptical of almost all such studies, and always look closely at the data and methodology to see if a confounding effect might contradict the conclusion. We should only give weight to studies that stand up to such scrutiny, and even then we should realize their limitations.