I find these posts very low value. Short sentences like these seem optimised for wit, rather than truth, usefulness or insight. While I suppose theoretically there's no reason why a brilliant and startling idea couldn't be communicated by a simple, short sentence, everything I've ever read on Less Wrong and found useful, interesting and new has been an idea that requires some explanation.

Several theories:

• A shorter sentence can play with language tricks, whereby something sounds profound without being so. A longer explanation by virtue of its length cannot sustain itself on mere language trickery.
• A more detailed explanation has time and space to fully, or at least partially, reveal and explore the implications of the idea, where a shorter sentence can sound wise but have no real implications.
• The more startling and potentially groundbreaking an idea is, the more actual work needs to be done to set it up properly. For instance, by itself saying "Thou art physics." while it might sound wise, wouldn't lead to a proper understanding of how that dissolves the question of free will. That requires a rather extensive explanation.