People expect the sources to have some sort of marketing scheme behind them. Examine.com is the exception by having well researched suggestions backed with actual studies and a status of being a reliable third party. I understand their skepticism, because of how much learning it takes to actually do supplementation safely and effectively. Most supplements just help based on placebo effect anyway, I aggregated the supplement effects studied on examine.com and 50% of studied effects were neutral. Only 8% of the supplement effects they investigated were more than minor, the numbers can only get worse when you consider publication and selection bias! So there is good reason to be critical, because the odds are against supplements helping enough to be noticeable beyond what a sugar pill can do.