These folks include presenting a false person as being of age, then switching to underage at the time of meetup when the target shows up.
A group descends upon the target who is now told they’re a pedophile.
Then the group tries to kill the person who was trying to meet what they thought was an adult.
And the perpetrators think this is justice.
I never really used Reddit, but I read an article during the API debacle in 2023 that mentioned Lemmy so I gave it a shot.