In the words of the NCAA to the transferee ... "Waiver: An action that sets aside an NCAA rule because a specific, extraordinary circumstance prevents you from meeting the rule. An NCAA school may file a waiver on your behalf; you cannot file a waiver for yourself. The school does not administer the waiver, the conference office or NCAA does." Aside: never read who filed the waiver here.
The link at the bottom, the best article I've read on the subject, explains this the context of the whole process.
Personally agree with the direction of most of the comments. This rule gives the NCAA the "legal" right ( in principle a power granted by the member schools) to do whatever with any specific situation and not have to publish a rationale to explain/justify the decision. As a result there are no records creating precedents or for public review.
As it doesn't seem like there is a meaningful way to "appeal" (not relevant here) the decision this ends up like the US Supreme Court turning down an appeal (although they publish the vote) without comment. As a result there could be some really good reason (doubtful though) that only the folks who made the decision would know for sure. Also possible a case might be well or poorly argued ... again no way to tell.
https://www.sbnation.com/college-football/2018/5/9/17311748/ncaa-transfer-rules-change-guide-list-sit-out