That the bottom 25% of scorers in standardized tests are in the bottom quartile of the distribution, which is literally defined as the bottom 25%, but the Twitter user seems to be using that fact to justify something yet he's literally just stating a fact?
The bottom 25% will always exist and there will always be 25% of the results contained within it.
Not sure how anyone doesn't get it, but this Twitter screenshot exists, so there's that.