I didn't shoot at him the last time I saw him, but it was almost dark, I couldn't be sure just exactly what I was looking at, and all the hairs were standing on the back of my neck. Plus, he was about 50 yards away and I had my Model 66 stoked with 158 grain hollowpoints.
Huge moral and ethical questions to be resolved on shooting an animal that may or may not exist. Am I shooting at an unknown species or some idiot wandering the woods in a gorilla suit? If I do shoot an unknown species, am I shooting a dominant breeding individual and might threaten the survival of the group? Are his buddies around? Might I have to defend myself on my way to the pickup truck?
On the other hand, is any rational scientist going to believe they exist without someone dragging out a big furry corpse? Some states have laws against harassing or shooting a sasquatch, so the hunter might be in violation of one or more statutes.
I don't believe I'd shoot one unless I were defending myself. The same basic premise applies as if I had to defend myself against a marauding bear, cougar, or human. But then, that's just me. Your mileage might vary.