...is dialect-beta'ing a sign of "elitism" in fandom? If you're writing American characters and you're not American, or are American but have been writing British/Aussie/etc characters, you might need extra help (re)acclimatizing yourself to the cadence and word choices. There's nothing wrong with this, and when others make helpful, kind posts that you can either 1) take into consideration, 2) ignore, or 3) rail against, why choose option 3? Why assume everyone is trying to make you, personally, feel bad for not being American? Or feel bad for making mistakes?
In Harry Potter fandom, in Sherlock fandom, in Torchwood and Doctor Who fandoms, there are British and Welsh beta readers who specialize in helping (mostly) American and Australian writers be more authentic. There are posts and communities on Livejournal and Dreamwidth dedicated to just this art. This isn't bullying; it's helpful! If you care at all about portraying your characters honestly, then you will care about the words that they use...which means you will care about their accent and dialect.
So when Derek says, "I'm going to fuck you properly," I will laugh! Not because I'm mean, but because it rings false to Derek, the Furry North American Werewolf. I might not backspace immediately (who knows what other gems are hidden in the fic?) but it does tell me that you were either 1) unaware that as a resident of NA and specifically California, Derek's idiolect would probably not include the use of 'properly' in this way, OR, 2) you just don't care.
#1 I can forgive completely.
But #2?
