As humans, we rely heavily on our visual abilities to make sense of the world, at least initially, and so when an image of something that does not immediately fit in our frame of reference is ejected from our brains as unclassifiable, we begin the search.
The Internet, as an electronic extension of the collective human brain is the first logical place to look.
Tons of people upload photos of stuff they've seen and can't figure out. Trail/Game cam pictures, summer vacation campground photos, panoramic tourist shots, we are rife with high quality cameras now but we still can't seem to get very good photographs of what many believe is just an oversized forest ape living in the great woods all around us.
Why not? What is so hard about obtaining one single, sharp focus, full daylight image of this cryptid animal?
Some say that it's Bigfoots terrific wariness. He (or she) is highly attuned to the presence of a camera (and guns if you prefer) and that his great physical prowess allows him to disappear too quickly.
There is merit in this position, if you have ever tried to take a photo of a wild animal you will understand. Wilderness locations, with big trees, bendy roads and mountainous terrain are not often conducive to obtaining easy imagery with sketchy availability of light and decent unobstructed backgrounds. Animals by nature tend to blend with they're surroundings, and if we add in the concept that Sasquatches are more nocturnal than diurnal, they have the additional benefit of cover of night to aid in their subterfuge.
So because they may be wary as well as nightowls, we are relegated to trail cams for our best chance at a good picture. Plenty of people use them, with varying degrees of success.
Sadly, the world of Bigfoot evidence is so bereft of clear VIDEO (as opposed to simple still images) as to make a baby cry.