See, the thing is that 500 years ago our ancestors invented FTL travel. Several solar systems were colonized, most with far better planets than Earth. Eventually, Earth was solely inhabited by the Luddites who feared FTL, and therefore they completely erased it from the history books.
Now you want to visit another solar system, but you are told it is physically impossible. There is no way to do it, the means of travel do not exist.
That is pretty much what it's like for the children in these kinds of sects to attempt to get a good education. The very knowledge that good educations exist are essentially kept from them.