Head in the clouds

You may have read recently that scientists have uncovered new evidence in Amelia Earhart. Scientists have compared an arm bone from a skeleton found on the tiny island of Nikumaroro with a photograph of Earhart's arm and determined they match. 
This adds more evidence to the compelling case that Earhart and her navigator Fred Noonan got off course and crash landed on Nikumaroro where one or both survived for a few days. A distress signal emanated from the island immediately following Earhart's disappearance, but rescuers were unable to locate the pair. However, just three years after the disappearance, a partial skeleton belonging to a woman of European descent, about Earhart's height. Found nearby were a buck knife, a woman's shoe, a sextant box, and bits of an airplane. All signs point to this being Earhart's fate, and CNN, the Discovery Channel, and tons of major news outlets are reporting this all as fact. 
But not so fast. Back when the skeleton was found in 1940, Dr. David Hoodless, principal of the Central Medical School of the South Pacific on Fiji, examined it. He stated that the pelvis "definitely" belonged to a man. The skeleton then promptly disappeared, and all subsequent study of it has been based on Hoodless' notes and drawings of it. 
As for the detritus found on the island? There's no good reason to believe that the stuff belonged to Earhart. Pearl divers frequently used the island as a base of operations, and the island was home to a British colony just a couple years after Earhart's disappearance. The assorted bits and bobs floating around the island could easily have come from any of those individuals, or have washed up on shore from nearby islands and ships.
Then there's the matter of the distance. Shortly before the disappearance, Earhart was in radio contact with the island she meant to land on, Howland. We know she was very close to Howland because the radio wasn't that strong. It is almost certain that as of her last transmission, she was in the immediate vicinity of Howland, but unable to land due to equipment malfunction.
Nikumaroro is 400 some miles from Howland, and Earhart's last transmission mentioned they were nearly out of fuel. She simply would not have had enough fuel to make fly that distance; in fact, to make it from Lae in Papua New Guinea, where they last took off, to Nikumaroro would have taken every last drop of fuel her plane could hold, and she'd have had to fly directly there - she could not have flown to within radio contact of Howland, then taken a sharp turn and flown hundreds of miles in the wrong direction - there simply was not enough fuel. 
As for the radio transmissions? The last transmission anyone is sure of came at 8:43 AM. There were subsequent signals, some of which came from near Nikumaroro, but there's no evidence those signals came from Earhart or Noonan. In fact, the captain of the USS Colorado, one of the battleships out looking for Earhart, says "There was no doubt many stations were calling the Earhart plane on the plane's frequency, some by voice and others by signals. All of these added to the confusion and doubtfulness of the authenticity of the reports."
On top of which, in order for the plane to transmit signal from Nikumaroro, the radio couldn't be submerged, meaning that the plane would have to have crash landed on the island, and the Navy didn't find any plane when they searched the island just days after the disappearance. 
Nature abhors a vacuum and humans abhor loose ends. That's why it's so much easier to believe the Nikumaroro theory than to believe what the vast majority of researchers do: that Earhart and Noonan ran out of gas and ditched at sea. But that conclusion is well supported by her last transitions alone - she knew she was on the island, she knew there was an equipment failure, she knew they were almost out of gas. Where's the plane now? At the bottom of the ocean somewhere near Howland. It's not a satisfying theory, to be sure. And searches for the plane in the area have turned up nothing. But the plane is small and the ocean is big and the ocean is deep, and the fact that the plane isn't easily found in one place doesn't mean it's somewhere else hundreds of miles away.
The Nikumororo theory is championed primarily by one guy, Ric Gillespie, principal of the The International Group for Historic Aircraft Recovery. And he really, really wants his theory to be true. Gillespie's really good at taking a few scraps of evidence that aren't very strong and weaving this really satisfying story, one he wholeheartedly believes. Every couple of years, he'll put out press releases or do an interview with "new" evidence, such as this whole arm bone thing, but the evidence isn't new at all. Gillespie, or one of his adherents, found a picture of Earhart in which her arm looks like it might possibly be the same length as the sketch of the arm of a skeleton that probably belonged to a man and has been missing for three quarters of a century. 

Sources
https://skeptoid.com/episodes/4295
https://skeptoid.com/blog/2012/03/20/more-amelia-earhart-nonsense/
https://en.wikipedia.org/wiki/Amelia_Earhart