Because in a post-truth world the person who controls wikipedia controls reality. Those fringe opinions can and do become true. Whether they are actually true in the past is irrelevant. If you can keep it on Wikipedia long enough people will act on it as if it were true.
Just look at what happened when wikipedia updated Pi to be 3.14159265358. Within weeks it started appearing in scientific papers. I'd bet good money that spaceX is using that number to launch spacecraft. Whether that is the true value of Pi is irrelevant. The wikipedia collective has decreed that that number and so it is now our scientific truth.