In that case, you're insulting not only every fanfiction writer but also every writer in general, and it's a little strange that you want to go after the craft at all. The idea that you're adhering to is a common misconception that a lot of young writers make in that it confuses the concept of themes with that of plot. A story is a lot more than the bare-bones structures you've mentioned, which is why not every story that follows what you claim to be the exact same formula is automatically popular based on genre or its underlying themes alone. While a lot of stories share similarities (because, yes, a lot of themes tend to be reused), this doesn't make every author a thief (because a good author would still find a way to bring something new and fresh to the table, regardless of limitations), and not every story has absolutely nothing new to bring to the table. After all, even if we do go by your logic, there had to have been a time when the basic themes were never done before, am I right? A new theme doesn't necessarily alienate an audience. It just depends on what the new theme is.
In order to be a good writer, this is really something you'll probably need to realize -- that a story is a lot more than its theme. You'll also want to think about its concept, that part of the story a lot of people tend to confuse for the plot. If you, for example, decide to write a story that's basically Pokémon without Pokémon, yes, some people will call you out on that, and you'll need to be prepared to handle that. Alternatively, you'll want to come up with a completely different concept that doesn't involve you explicitly taking the story of Pokémon and just removing any instance of the word Pokémon.
(Side note: Strangely, I can name a number of series that do a lot of things you've mentioned. Pokémon has its own currency, for example. H.P. Lovecraft's bread and butter are Eldritch Abominations. Sherlock Holmes short stories frequently spew out plot twists. And so on and so forth. It's really all in what the author intends on doing. Sure, there's such a thing as screwing things up royally, but there's ways to pull things like these off without actually alienating an entire audience.)
Either way, you'll want to avoid stating that it doesn't matter whether or not you're creative in the plot bunny thread, where the whole point of the thread is asking about whether or not your concept is particularly creative and potentially enjoyable. Because that's just counterproductive.
It also strikes me as a little odd that you're trying to claim that calling everyone in a forum a thief isn't going to be an insult that ends with you alienating your potential audience anyway, but hey. :/ However, I would like to say as a side note that if you really want to argue this point, I think I'll just end the conversation there because it's really become clear to me that you're not particularly interested in concrit.