There were a LOT of angry Tolkien nerds. A LOT. Now, I definitely think the films are infinitely better than the show, but both are pretty removed from the original work. The show is worse because it is more badly written, not because it deviates from the lore.
Yes it is indeed badly written. And a significant part of the bad writing is how stupidly it deviates from the lore. The majority of Jackson's deviations were in the interest of brevity and didn't dismiss important timeline milestones. Yeah, I hated the wizards breakdancing battle and the death of Saruman. I wasn't a fan of Arwen absorbing Glorfindel's role. I missed the Scouring of the Shire. But none of these resulted from bad writing that showed disrespect for the source.
But as for the show, I can begrudgingly accept shortening the multiple millennia timelines of Tolkien's Second Age. But there's no excuse other than hubris or incompetence for injecting Third Age characters who won't show up for 3 to 4 thousand years canonically. And it serves no purpose whatsoever to have The Three in existence before the crafting of The Nine when they were forged nearly a century afterwards. Also it should clearly be stipulated that the Galadriel of the show is indeed a different character from the wife of Celeborn and founder of Lothlórien. Both of which happened before the creation of any of the Rings.
*MySmiley*
"Bustin' makes me feel good!"
Ghostbusters, by Ray Parker Jr.