Paradoxically, people who get angry at the "Was Brandon stupid?" (by going to where the Mad King was and Rhaegar and Lyanna had no reason to be, "conveniently" straight to his expected death in those circumstances) would be validated in such criticism being misplaced against him in the case that Brandon genuinely believed so with good reason by being lied to in such specific terms about whatever information came to him from the spot of Lyanna's disappearance.

The paradox comes from such crowd's wish to exonorate and pity Brandon, but not Lyanna, hence sticking in that dead end. Quite the contrary, the whole purpose of the outrage is solely to incriminate Lyanna - and of course Rhaegar.