I once had 11 different people, all friends, accuse me of doing something bad(littering). Literally everyone was confident I did it. They all saw me do it. Everyone piled on me to just admit I did it. I said I never littered, that I hate litterers, and that I have never even eaten the kind of food item that the wrapper came from. They got even madder at me for denying that I did it, as if I was trying to gaslight them all.
Email threads were started where one person collected everyone's recollection of the events, who was there, and what happened. Every response lined up perfectly with each other. I don't think anyone explicitly coordinated their accusations, but knowing there were multiple other accusers certainly made the accusers feel more comfortable and correct in their accusations.
I was presented with the evidence, literal written testimony of 11 people who I considered my friends at the time. I was given an ultimatum to admit it or be kicked out of the group. I said I wouldn't admit it. I started looking at each person's recollection.
You know what actually happened, that all 11 people missed? There were actually 13 people in the group that day. The 13th person, that absolutely everyone forgot about, was a person who didn't normally attend the group. He is 6'10" and 350 lbs. Hard to miss. But everyone forgot about him. I called him up, put him on speaker phone in front of everyone, and asked him "Did you eat last time we hung out?" His response "yes". I then asked him "Did you throw the wrapper on the ground?" His response "yes".
I asked my friends if that settled the matter, and everyone still believed that I was the litterer. So I stopped hanging out with them.
Nobody was vindictive at the start. But they were all so confident of their own recollections that they became vindictive when I said that they weren't remembering things correctly.