Why do so many claim theories as fact?

The truth behind Theories are they are only ideas of the human imagination, some more than others are more likely to have a chance of standing as being true.

BUT …. With out evidence to support an idea ; We as a whole can not claim theories to be true by any means.

(Research must be conducted)

BIGFOOT …. In the world we live in that has so vast of large uncharted forests all throughout our world we as enthusiast and or Researchers that have a stable mental mind do not see bigfoot on a normal bases or we are fortunate to even see the creature at least once in our life time.
Some on the other hand have an over active imagination of seeing what they want to .

There is a great explanation for these claims and theories that flood our bigfoot community.
Science that is not understood , and education or awareness of our own living species living in their own environment, and how they are made and or adapted to live with natural elusive abilities.
A deer or a bear are great examples of blending in the forest, these animals can disappear with simple movement behind the foliage that surround them.
Primates in their own world are great and masters of hide n go seek.
EXAMPLE – Primatologists who spend their time in the jungles and forests observing the variety of our known primate species acknowledge the simple elusive disappearing act that they do when moved into the foliage that surrounds them in their environment.
(Even within a few feet away)

So without getting to deep into further explanation be sure you consider, nature, science, and reality.
Do not rule the obvious, know the truth