Because they have zero credibility on absolutely any other subject after the 2016 election.
A deeper, and more cynical view, is that traditional “old Democrats” like Harvey Weinstein are simply caught up in the drama of the Democratic party trying to figure out how the hell it can regain some semblance of being an actual party and not the Clinton’s family business, and the armed propaganda wing of the Democrats is doing everything it can to help “purge” the corrupt old guard that lost the last election. You see, Harvey, your money is only good enough when they win.
Just saying that I don’t think the press would be focusing on sexual assault or harassment if Hillary were president right now. Because the big money donors would be on the “right side” of the ruling elite. Since the old big money didn’t win this election, the Democrats are infighting, and the press is doing their best to support the changing of the guard to help the “New, Improved Democrats” look like they really are doing something for women’s rights.