By “belief” I mean that the evidence is not conclusive to prove existence, at least from a perspective of reasonable scientific skepticism. For instance, compare the body of evidence for the existence of bigfoot to that of grizzly bears – accepting the existence of one of these requires much more “belief” than the other.
Regarding the footprints, etc. – I do find those things odd. They are very odd. Unfortunately, none of these odd things are conclusive, and many are easy to fake or could conceivably be misinterpreted.
What has hands to throw rocks? People do.
What made those prints? Maybe bears, maybe hoaxers, maybe pink fuzzy unicorns, who knows? Maybe they’re not prints at all.
It’s easy to assign difficult-to-explain sights, sounds, smells, experiences, flying rocks, “tree breaks”, etc. to a loosely defined fictional creature because it has no rules, no standard – it’s made up. See/smell/hear something weird in the woods? It’s bigfoot. How does one argue against that?
Suppose bigfoot exists, and we learn that it is incapable of uprooting, inverting, and pile-driving that 30’ tree into the ground from Bigbill’s link. Or we learn that they don’t smell bad, or that they don’t make shrieking howls, or they can’t throw rocks. Lacking an obvious explanation for these phenomena, would we then have to attribute them to some new made-up creature? A bigger-foot, perhaps?
Oddest of all (IMO) is that, as I said before, it seems bigfoot enthusiasts have relatively little difficulty finding or experiencing “signs” of bigfoots, even interacting with them, but nobody has ever found even a partial specimen that can be verified. No amount of inconclusive, questionable evidence adds up to legitimate proof. And a large, globally widespread, terrestrial mammal shouldn’t be this hard to prove.