If you come into an existing game, any game and I do not care what 'official' comms the pups are members of, and ask to replace an existing player because you want their character and are told no that does not mean you are blacklisted. That means you have tried to force your way into an exisiting group of loyal players who don't cut each other loose for no reason. That means people are not going to unravel a year or more worth of collaborative story telling just so that you can make the character 'canon' as you see them.
Further, you can't cry "blacklisted" and "McCarthyism" when you were welcomed into the game with another pup. If you want to hear cries of "foul" why not tell people about the way you started IMing the members fo the game asking them to RP with your character exclusively or asking the other mun to step down from her well-played and long running pup? Or that you pick up all of your toys and run home when people tell you that they won't acknowledge a duplicate pup in the game?
One last thing, there is bowing out of a game gracefully and there is being an utter and complete shithead. You chose the latter. Instead of informing the people who allowed you to bring your cross fandom muse into our game that you no longer wished to play with us for whatever reason, you wrote and AU exit post for your character and then decided that we were not supposed to acknowledge it. Grow the fuck up.