You are right. There is no real mystery. Mankind has known about these animals for tens of thousands of years.They are a primitive member of the genus Homo. They, like Homo Sapiens, have diversity in their appearances, body shapes & sizes, hair types, eye colors, vocalizations, traits and habits. Forensic Hair experts have long classified human hair sample by three basic types:Caucasoid (European), Mongoloid (Asian) and Negroid (African). There are at least three "types" of Bigfoot. Each "type" has hair which is nearly identical to one of those basic human hair classifications.
When earlier settlers actually killed some of these creatures to protect their homes and livestock, the settlers had no access to scientists nor had any interest in the "science" of Bigfoot. (The body of a young Bigfoot was for many years displayed in the court house of a very rural, deep-south county. It was only removed in modern times by a high level official in the state's fish and wildlife agency who went there, along with a field warden, to testify in a trial. That fact was confirmed by many older residents - some were previous county officials and law enforcement officers.)
Generally science nor federal and state wildlife agencies have wanted any part of the Bigfoot situation during the years. To them the declaration that the animals exist would be an uncontrollable bomb. And they are right for many reasons. But now, because of the human DNA carried by the animals, a Presidential Memo issued by Mr. Obama, and directed at every division of of federal government and every science lab in the country that receives, directly or indirectly, funds from the federal government, is prohibited from scientific examinations or research on "humans" without their written permission. (The law provides that if a scientist(s) know that such actions have occurred, and does not report it to the feds, they will be punished.)
The DOI and the DOA - with help from any branch of the military they need at any time - are doing all they can to provide huge areas which are designed to try to make accidental encounters between average folks and the animals less likely. (Based on the huge increase in the number of sighting reports during the last few years, the worth of those projects are questionable.)
Bottom line: The tens of thousands of folks that know about these animals, and don't want them "shot and put on the slab" should be somewhat content. Those that don't know and don't care are probably better off. Those that are certain in their own minds they don't exist but want to convince those that know that they are just fooling themselves are simply SOL and will have to be content banging the keyboard.