Ehm... https://money.cnn.com/2017/11/02/media/house-of-cards-kevin-.... There were eight people working on the "House of Cards" who alleged/confirmed he was predatory. There is of course still a chance that it's one big witch hunt, but this is definitely not a case of 100 Twitter random users making a lot of noise.
But hey, now some guy on hacker news says his friend witnessed it...
Or you can go to Wikipedia to find a list of accusations (sourced with articles written by journalists) and evaluate whether you find the claims credible based on the journalists/newspapers/people/accusations involved.
I think it's perfectly okay to claim that all of these people involved are lying and it's just a big conspiracy, but at least provide some arguments to this specific case instead of vague "oh, but can we actually trust words on the internet???".