If BYU was in a P5 conference, then Washington's conditions would be absurd. But Washington was giving BYU a chance to play a real team. If Washington was forced to cancel (by the P12) at the last minute, then BYU would have received a BUMP in sympathy and rankings for being treated poorly. Instead, BYU has lost its narrative.
Also, if UW's demands were so ridiculous, why did SDSU immediately say--we'll play in Washington!? Because it's a great opportunity, especially in a year when games are hard to come by. Is there some risk that the game would be cancelled? Of course--games are being cancelled left and right at the last minute every week. But that's all the more reason why BYU should have jumped at the chance to make it work.