An article about a topic doesn’t mean it’s endorsed - are you seriously suggesting that Wikipedia shouldn’t host an article that describes a theory if you don’t like the theory?
Are you seriously suggesting an encyclopedia should be packed with crackpot conspiracy theories, academic charlatanry, quackery, and agitprop? Or does that not defeat the point? Keep the author's biography, but his "theories" are best left for a footnote in the biography, or websites that explicitly serve as a museum for failed ideas.
A) that’s a very biased view of it that you clearly are emotionally invested in B) an encyclopedia should describe all things factually. It’d be one thing if it described it as truth, but describing it truthfully is far different
Since you can just counter anything I say with calling it “anti-knowledge,” I’ll leave you with a profound quote:
“That’s just like, your opinion, man”