A lot of those islands are due to the many conflicting theories and personalities in this field.
Since so many people have such passionately held beliefs about the nature of this phenomenon, delay groups develope along those lines. Pro-kill, no kill. Flesh and blood vs paranormal. Humanlike vs apelike.
David Paulides, Les Stroud, Scott Carpenter, and the howtohunt guy have all kind of aligned due to some shared beliefs. Then, there are groups who are vehemently opposed to them.
As far as the noise levels go...one man's noise is another man's music. What I consider to be useless sometimes made up information,others might see as the gospel truth.
If you are looking for decent podcasts on the subject, you can add Sasquatch Chronicles (although Arvedis will disagree with me on that one) and Bigfoot Eyewitness Radio. William Jevnings puts out a podcast called Creek Devil, which I don't care for but others enjoy. NAWAC has a podcast called Apes Among Us that is pretty informative.
Facebook groups have been more than useless for me at least, with the exception of sometimes finding a regional news piece on the subject that I might otherwise have missed. I am sure that there are tiny little nuggets of gold scattered among the dirt there, but I don't have time to sift for it. The same goes for Reddit groups. Most of those groups from both platforms are filled with Bigfoot memes, pictures of Bigfoot coffee mugs,and barely literate diatribes attacking those who have broken the author's personal code of Bigfooting.
Honestly, these forums are probably the best way to get a wide range of theories and connect with other researchers. Like everywhere else, there's a lot of conflicting theories here, but everyone meshes together we'll enough.