Science has to start somewhere. Actually proving a causation is hard and expensive and usually needs to be very targeted. You need these kind of feeler studies to find promising links to target for further research.

This is why science is so much about standing on the shoulders of giants.

It is wrong for journalists to report these low rigor, survey studies as the meaningful results they always seem to report, but for some reason Women's Health can keep saying "Chocolate causes cancer actually chocolate cures cancer actually chocolate has no effect on cancer actually...." for decades and people don't stop buying it and instead insist that the scientists are the ones lying