Perhaps because even the first URL you chose, WebMD, admits that there is no evidence any of those benefits exist…
How does it work?
Turmeric contains the chemical curcumin. Curcumin and other chemicals in turmeric might decrease swelling (inflammation). Because of this, turmeric might be beneficial for treating conditions that involve inflammation.
Might is exactly what get with unfounded claims that haven’t been scientifically confirmed.
And the second link, “food facts’ is effectively a blog for Dr. Mercola’s Premium Products website. Guess how many different curcumin supplements Dr. Mercola’s site sells? Eight! https://shop.mercola.com/search?filter=&search=curcumin&type=q&keywordoption=CUSTOM&cid=0&fltrdesc=
For years actual medical professionals were convinced that ulcers were caused by diet, stress, caffeine, etc. And they were all wrong. Do you really think that because a lot of people spent years believing in some holistic or herbal treatment for medical issues, that proves it works? Scientific evidence is what proves if something works. Right now, there is not remotely enough to justify claiming that curcumin treats anything.
You can choose to believe that it does these things all you want — and you’re free to use it however you like. But you cannot rationally argue that there is any actual empirical evidence to support that choice, or complain when people point out the lack of scientific evidence to others, who might still be deciding what treatments they want to put their time and money into.