And me, as an outsider on the internet, has no business trying to pick a side or work out who should be punished. That's the job of the legal system.
Assuming a two-party interaction, for every person that makes a true accusation of abuse, there is one malicious actor (the abuser). For every person who makes a false accusation, there is one malicious actor (the accuser).
Regardless of the ratio of true to false accusations, the number of malicious people in the world remains unchanged.
So it would be expected that almost every accused person would defend themselves when they would not lie if the sides were reversed.
Because effectively you are saying that this kind of bad behavior is more likely than the bad behavior where one person would lie about another. And it is not clear why you think one type of antisocial behavior is more common. People lie every day, oftentimes to their own detriment. Likewise people are creeps every day, again often to their detriment. I think it is far from clear at this point which behavior is more common.
In a pool of one hundred people, where one is an abuser and nine are false accusers, you'll have one false denial and nine real denials.
If it's nine abusers and one false accuser, you'll have the opposite ratio.
Without demonstrating which toy world applies, you can't know what's going on.
We're throwing away "innocent until proven guilty" with this. I'm sure you agree how dangerous that can be.
Though, as you point out, recording every moment is not feasibly or desirable. Do you have any ideas on how we could solve this problem?
Making it easier and cheaper to file defamation suits wouldn't help as in this case there was no evidence.