The word “theory” has definitions outside of the context of the scientific process, and it’s pretty obvious that MatPat was not doing anything scientific in his videos. I don’t understand the concern here
The word “theory,” when used in a scientific context, indicates a well-established idea supported by an immense amount of peer reviewed data. While I understand that many people use the word “theory” to mean “random unsupported thought,” the use of the word in that context is just as egregious as the use of the word “literally” to mean “figuratively.”
And while you’re right that MatPat’s videos were anything but scientific, you’re wrong that it was obvious; I’ve heard plenty of people recommend his videos to me, describing his channel as “taking a scientific approach to video games,” which is another way in which his videos downplayed the stringent work that the scientific process requires to be accurate and valid.
We live in a time where, in spite of abundant access to information, an alarming amount of people legitimately believe that climate change doesn’t exist, that vaccines cause autism, and that the world is flat. We can’t afford to be even tangentially undermining the authority of the scientific process.
Game Theory is a hard mathematics concept and not an applied scientific theory, so you’re in the ballpark but slightly adjacent. The fact that so many people can graduate high school without the basic understanding of the scientific method and the differences between a hypothesis, a theory, and a scientific law is concerning, I grant you that, but the number of graduates who can’t read proficiently is even more concerning.
MatPat may not have been a Mr Wizard, Beakman, or Bill Nye, but he was not the worst Pop-science entertainment platform out there. Just like comic books didn’t corrupt the youth and kill reading for the generations since the Golden Age, I doubt the Game Theorists did much harm to the public’s knowledge of science. It is not the job of YouTube entertainers or ticktockers to teach science, and if a few people become interested in science because of channels or programs like these and go on to learn more or focus in STEM in school, then I think that’s probably a net positive.