I didn’t say that. And neither does the article. It says, he’s been accused and denies it. That’s literally the extend of what’s been reported and what people are saying.
What I did say is that usually the most proof you get in these cases is someone backs the accusers story in some way. (Which again, does seem to be the case here since the company they work for deemed it believable enough that they ended their relationship with him.)
Particularly because it includes assault in the category, which often can be proven but also because while sexual harassment often can’t be proven definitively, claims can be said to be reputable, usually because their backed by other accounts.