I still say it's silly that it's ok to "change" lore surrounding witches, wizards, unicorns, giants, trolls, and what-have-you to build a fictitious world, but if you use creatures from other folklore than "Western European" (she mixes liberally from German, Saxon, French, Latin, Greek, Christian,...mythology, after all), it's suddenly horrible recuperation. I promise I won't complain about a Native American writer using "trolls" in a slightly different way than originally envisioned or as they're traditionally interpreted.
I mean, you can, of course, use them as clearly insulting - Djinns were often used as demon/devil stand-ins in Western fiction based in or around middle-eastern stories for example - but as far as I know none of what JKR wrote so far's been casting Native American beliefs in a negative light. Of course, she did shy away from calling Jesus pretty much just a strong wizard from before they went into hiding, while she does happily repurpose other religions' beliefs or myths as stories about magic....Eh.