I'm fairly certain that exists, but it's actually not a requirement to never have false accusations before justice can be pursued.

In the same hypothetical where character assassinations can be organized and bring someone down with false accusations, the same can be true of defending someone as well. Multiple people coordinating by speaking in defense of someone against accusations are just as possible.

I'd even speculate and say there's more instances of coordinated defense happening more often than false accusations, as powerful people being protected from accusations is what started MeToo