Your rebuttal of this "pseudo science" is that you perceive that you personally need 8.5 hours sleep - now that smacks of pseudo science to me.
People are very different. Just because 1 person in a 1000 (or 100 or million or whatever) benefits from 8.5 hours sleep does not necessarily mean that in general one might get more benefit from less than 8.5 hours sleep.
This is not hard science, I doubt it could ever be, but that does not mean it is pseudo science and certainly should not be dismissed out of hand because it does not fit into the model of the world that you have personally.