If I understand correctly, the person who coined the term does, or at least claims to.
Oh, do you remember details differently? That’s very common.
That’s not how I remember that episode going.
A false memory can be something that just a single person mis-remembers. The Mandela Effect refers to false memories that are relatively common in the population, not just one-off errors of recall specific to a particular person.
Or, equivalently, false beliefs that a significant portion of the population can be suggested into remembering. If the Internet existed decades ago, people would be asking “Remember that movie when Cary Grant said ‘Judy, Judy, Judy’? No one can find it, now! Schweitzer Effect!?!”
People heard Grant impersonators say “Judy, Judy, Judy” a lot, possibly following Larry Storch, who was doing a Grant impersonation when Judy Garland came into the room (Article - "Judy, Judy, Judy" - The Ultimate Cary Grant Pages); it’s no surprise that people came to believe that it was a quote from an actual movie.
Or better impersonators who did it much more realistically.
That reminds me of a Kurasowa film, but I might be mis-remembering.
My memory is not reliable, so the first time this happened to me, i assumed I was mistaken. Then it kept happening. But all of you are right. There are many possible explanations for this.
The way I remember the Mandela Effect, everyone definitely thought it was because of alternative universes. I have a clear memory of them all saying that.