Well, there is a contradiction for you. The link that you gave here leads to an excellent introduction of the inner arts. Several of the important concepts are mentioned and even a bit explained.
So it proves my point - it can be discussed.
It can also be described, just as we can describe just about anything in this world.
It proves another point - several proponents of IP / IS do not seem to know these basic concepts (as mentioned on the website) or are even against it. Some have even expressed this clearly in this very thread. At the same time they claim knowledge that nobody else has. That is a contradiction too.
If someone does not understand these basic concepts then a more modest attitude would be more fitting.
Nobody ever said that it couldn't be discussed, you're setting up a strawman.
Like anything else, there's a point beyond which that becomes impractical at a distance, especially if the two people in the discussion don't have a common context for discussion.
I don't see how that link proves that anybody understands or doesn't understand anything, you'll have to be more specific.