Seriously, it is.
Everyone wants to be original - worse, everyone thinks they actually are original. So much so that they take exception to being told someone else had the same idea before.
Asked to look over a proposed outline for someone, it took me all of one sentence to recognize certain aspects from an extremely well known series in the same genre -- right down to the organization names and history of the main character.
Sure the character's name wasn't the same, but I'm fairly certain that a simple rededication ceremony would have made this particular piece a well plotted piece of fanfiction. In fact, I'm not at all certain that it didn't start out as just that.
The author didn't want to hear it... no matter how many 2nd opinions she got that all came back with the same impression independently of on another. She had a full list of "yeah buts" ready to defend her "original" idea.
What she didn't understand was that original =/= "I didn't copy this from anywhere". At least it's not in the writing world. For writers, original = I got there first.
This is where people get upset that the idea they "had first" was "stolen" by someone else. It doesn't matter that they only started querying a book two weeks ago and the writer whose book hit shelves today never corresponded, or that it takes at the very least MONTHS (more likely over a year) for a book to hit shelves, as far as the querier is concerned, they've been robbed.
Just look at the people who've accused well known authors of this.
All it takes is a similar name or concept and suddenly, the little newbie is envisioning their face on David's body as they face off with the literary Goliath. The books don't even have to be that similar for the accusations to fly. There may be no proof that the published author every even heard of the newbie (and it's more likely they didn't than they did... the Internet is a big place full of people who all think they're going to find an audience.). Feathers get ruffled and feelings get hurt because suddenly the newbie finds that their idea isn't as "original" as they thought it was.
Now, when they pitch their idea, they feel that it's somehow diminished. They anticipate being called a "copy cat", or worse, fear they'll be rejected because the other one "won't allow" anyone else to succeed in their genre (which is ridiculous). Nevermind that their story is still as good or bad as it was those two weeks ago when they started querying.
The thing you have to remember is that ideas are cheap. They're so cheap they're worthless.
Also remember that people exposed to similar input will produce similar output. No two stories will be any more alike than the people who wrote them - and both can be successful. Execution is everything and that depends on skill, voice, and characterization.
It's also worth mentioning that, unlike a marathon, the first one across the finish line doesn't always win in writing.
Sure, a well known author will get a huge initial sale count for a new book, especially if it's had a big publicity push. Stephen King could probably put his name on a phone book and sell several hundred thousand copies before anyone realized that it was a literal phone book and not a novel by that name. He's Stephen King, he's a brand, and he's a good one. (He's also savvy enough not to put his name on a phone book and sell it, but that's beside the point.)
A new author may not have big sales at first - with or without that publicity push, though "with" certainly helps - but if the story is solid and the characters sparkle and the dialogue is like watching a really good movie... it'll click. The stars will align and the books will fly off shelves so fast the publisher gets that special adrenaline jolt known as the second print run.
It doesn't matter that the book in question is the 2,795,622 were-thingy/fairyland novel ever written. It's good, and people love it for that fact.
Don't get so hung up on being original that you miss your chance to write what you're good at and cost the reading world a potential gem.
Everyone wants to be original, but very few can pull off "good". Personally, I'd rather walk the less crowded road.