@Sampson Simpson
Yes. Good post--thank you for your contribution. Your story is touching base with the central focus of this Thread.
Now, the question is, how do we attempt to make sense of this? How could one's ability to see the world in great detail be quite advanced in some area (that they have studied) & incredibly below average/infantile in other areas that they have studied? What does this say about Human intelligence (or lack-there-of) more generally?
It shows that we have a poor understanding of what intelligence means. We tend to think of intelligence as a single attribute that describes the entirety of a person's mental capacity; but this model doesn't seem to match reality. I think Howard Gardner gets a bit closer to a good model for understanding mental faculties with his theory of multiple intelligences. I think Gardner's categories are a good start; although by no means are his categories exhaustive.
I believe that we are wrong to think of intelligence as a single attribute; that there are a variety of attributes we could measure and that someone who scores highly in one area may be deficient in others.
I know a medical doctor with a PhD from Harvard who, not only believes 9/11 was an inside job, but also subscribes to a lot of homeopathic quackery. You might forgive his ignorance of 9/11 due to his degree being in medicine; but how can he promote homeopathic nonsense that has already been disproved and still have a degree in medicine from Harvard? Dr. Oz is a more famous example of this; a Harvard trained heart surgeon...and quack.
I believe such examples show that these people are highly intelligent in some areas; the areas that would help them excel in medical school, areas like memory and problem solving. Yet they are lacking in areas having to do with how well grounded in reality they are.
We just don't understand the brain. You can be smart in some ways and dumb in others. Don't you know people who are incredibly book smart but lack any common sense?
Having said all of that; I think it's also important to avoid the temptation to believe that everyone who disagrees with you is somehow mentally deficient. I think when it comes to Young Earth Creationism, it's legitimate to posit that possibility, but by no means should we assume it is always the case. It may well be that there are Young Earth Creationists far more intelligent than you. Why do they believe this despite all of the evidence? Maybe because they simply place greater faith in their beliefs than they do in science. That doesn't indicate a mental deficiency, it just indicates they made a different (subconscious) choice from you in developing their worldview.