I guess pretty much every did know. Seems like Damon probably did know as well.
Just to make it clear McGowan is indeed claiming this. It's pretty clear from all the tweets and comments, this is referring to Harvey Weinstein.
This includes McGowan’s response to an official statement issued by Affleck’s Facebook page, in which the Good Will Hunting actor said he was “saddened and angry that a man who I worked with used his position of power to intimidate, sexually harass and manipulate many women over decades.” Calling the “additional allegations” against Weinstein “completely unacceptable,” Affleck said we “need to do better at protecting our sisters, friends, co-workers and daughters… support those who come forward, condemn this type of behavior when we see it and help ensure there are more women in positions of power.”
As righteous as Affleck’s comments appear, however, McGowan said he wasn’t being entirely honest. According to her tweet, the actor allegedly exclaimed, “GODDAMNIT! I TOLD HIM TO STOP DOING THAT” when she told him what had happened at a press conference they both attended. “[Y]ou said that to my face. The press conf I was made to go to after assault,” she concluded. “You lie.”
Edited to add in the latest allegations of rape against Weinstein. These are but probably a few. I shudder at all the poor women who can't afford to blow up their life with such an admission. I wonder how far this can of worms opened by Faraci will go.
Three women—among them Argento and a former aspiring actress named Lucia Evans—told me that Weinstein raped them, allegations that include Weinstein forcibly performing or receiving oral sex and forcing vaginal sex. Four women said that they experienced unwanted touching that could be classified as an assault. In an audio recording captured during a New York Police Department sting operation in 2015 and made public here for the first time, Weinstein admits to groping a Filipina-Italian model named Ambra Battilana Gutierrez, describing it as behavior he is “used to.” Four of the women I interviewed cited encounters in which Weinstein exposed himself or masturbated in front of them.