For bigfoot knowers/belivers only, I see it like this:
If BF exist, and if they spend any significant amount of time in our dimension as corporeal, flesh and blood creatures, then I find it difficult to believe that the gov't at large (and most likely academia), or at least a certain group (or groups) within, does not have knowledge of their existence based on remains, physical traces, or film/photos/video.
If BF exist, and are not F&B beings, then the gov't/academia may or may not be aware of them, but if they are, then the knowledge of their existence would obviously need to be based on something other than physical evidence.
Of course, if you do not believe that sasquatch exist, then the question is moot, an exercise in folly.