It's funny how your tone has changed from the scornful "it's still crazy to me that anyone thought this was a good idea" to praising Yale for "their long, thoughtful writeup" and "a carefully worded and researched examination of them earnestly pursuing the policy on academic grounds".
1) It wasn't a crazy idea. As ejb999 noted, a number of colleges had already done it before the pandemic.
2) It wasn't crazy to suspend the testing requirement during the pandemic.
3) It wasn't crazy to continue an experiment that had already been in progress in order to get conclusive results.
4) Yale didn't say the policy was a disaster. They simply decided that the other policy is better for them, in light of the empirical results.
5) There was no official end date of the pandemic. Thus, different institutions will move at a different pace. And Yale also mentioned as a factor for them, "With testing availability now fully restored for prospective applicants around the world".