The elephant in the room is that true randomised controlled trials take decades to do and even then are almost impossible to build in a way that teases out nuan

The elephant in the room is that true randomised controlled trials take decades to do and even then are almost impossible to build in a way that teases out nuances such as the specific effects of individual compounds within a supplement. So we are effectively left with pseudoscience as the only other option, but what would you rather do - sacrifice all of the insight and knowledge we are learning at such a rapid pace in medicine today, just because there's no feasible way to prove it within your lifetime (like, if you wait 20 years for observational studies to show that humans benefit from Omega 3 you will have missed the entire window when it would have been beneficial). We have to find a balance, but it can't sit at the extreme of requiring everything to meet an impossible bar of scientific proof before we start to benefit from it. But the price to pay is that some of them are not going to pan out.