Except rarely is it merely a belief that the earth is flat. It is almost always paired with the idea that they are superior, have knowledge others are too stupid, duped, and/or uneducated to be aware of, and anyone who does not adhere to their model is deceived, buying wholesale the lies that we are bombarded with from the likes of many highly educated scientists, astrophysicists, astronomers, etc, and especially NASA.
I disagree with your use of 'Except rarely' and 'almost always' as depicting reality. While it is true that there are some Flat Earth folks who may take such a stance or exhibit such an attitude - I believe that to be a reflection of their own personality - they are probably like that with other things as well. I believe most Flat Earth folks actually take a more 'humbled' approach and only want to share what they have discovered to be real and true.
I think a lot of what you are describing here is self-inflicted - assumed by those who have too much pride to admit to themselves that what they have been told could possibly be true.
I have no problem telling you that you have been deceived all of your life about many things - because, I believe it to be true. However, it is not because I think I am 'superior' or that you are 'stupid'.
The "knowledge" is available to any-and-all who are willing to open their eyes to see it.
And, level of education has nothing to do with it. But, willingness to swallow your pride has everything to do with it.
There
is no "special knowledge" -
that is the whole point - it is the "scientific authority" that claims to have "special knowledge" that you do not possess - which you choose to believe rather than trusting your own observation with your own God-given senses. Flat Earth folks tell you the knowledge is
free -
[that] all you have to do is look at it - but, you would rather live in the MATRIX with your ears, eyes, and mind closed.
You really are deceived if you directly equate or relate 'highly educated' to/with [the] 'real truth' without thinking - never questioning - never verifying - what you have been told.
And, therein lies the real problem - people don't want to think for themselves. And, they would rather place "highly educated" people on a pedestal rather than hold them accountable to the claims that they make.
There is more truth in these two statements than most people are willing to swallow their pride long enough to consider:
"Most people don't really want the Truth. They just want constant reassurance that what they believe is the Truth." (Author Unknown)
"Truth is available only to those who have the courage to question whatever they have been taught." (Author Unknown)
You would do well to consider the great volume of truth contained in these statements.