Do you know, this actually is one of the least helpful replies ever, and I see it all the time.
If he made a mistake, correct him. Tell him where he went wrong, let him know which point in print he misunderstood. Or, have the guts to just call him stupid and move on, because "reading is fundamental" is really just a way to say that while attempting to look clever.
Congratulations on the treaty, I think both alliances are going to benefit from having such great allies