People who did not hear the disclaimer at the beginning of the 8:00 PM airing of the program on October 30, 1938, actually believed Earth was being invaded by Martians. Police officers even called the radio stations because the performance was so convincing!
I'm sure you can find reports of people being exceptional due to believing this radio program was a legit news report.
Fun fact: the idea of millions of people panicking and believing it was a real news broadcast is
greatly exaggerated, or even false. But it still proves the point, because it's the sort of thing people learn about and believe because it matches their view of the world, and when the facts get in the way they have a tendency to ignore them - cf also the
Kitty Genovese murder.
So in the case of Vic, these women all believe that a handsome, popular, huggy guy can and would abuse women, that as a Christian he would be homophobic, and so on. So they think he's creepy, and everything that he does or has done just reinforces that belief even if it turns out to be impossible to have happened - and to them, being creepy also logically means he's an abuser and a rapist and probably even a pedophile. That the evidence is either debunked, second-hand rumours mostly anonymously spread online at best, or doesn't actually count as sexual assault doesn't matter - because they have their story that fits the way they think the world works.
And even though it turns out it's full of fabrications, large exaggerations, and is even most likely being pushed by people who have a specific agenda to make up this narrative - that's not really relevant, because Vic being guilty
feels true to them, and they have a strong case of
the backfire effect going. Which is bad enough on its own, but nowadays doesn't just make them dismiss any information counter to their beliefs, but also makes them dismiss any source which gives information they don't want to hear.
Which is why they focus on dismantling Nick so much, because he's an authority source telling them exactly what they don't want to hear. But if they call him blackface lawyer or claim he's running a grift, they can dismiss all his legal knowledge and information. It's also part of what makes the Farms so important to discredit as well, because above all else we provide receipts. Fortunately for them, we're already regarded as internet sewage, so our information, and questions, and quotes and screencaps and archives are easy to dismiss as well.
The tl;dr? Feels over reals, a story you believe trumps reality, and zealots in a bubble will actively attack the truth and those who tell it. To them, the Vic rumour has gotten so big I don't think anyone, not even all the VAs and Funimation combined, could say it was a lie and have them accept it.