Because it's hard. Seriously. We tried to add all possible scenarios that could occur when you check a website for copyright and usage terms, but it became a never-ending "choose your own adventure story." A story that usually ended with us requesting permission.
As a result, the Website Permissions Decision Tool is intended to teach you to evaluate - quickly - if we can use a website in a course. In short, it identifies conditions that disqualify a website and obvious conditions that make a website allowable. Hopefully, this process will save everyone time.