Another example: the school system in Oakland, CA, in 2015 abandoned its phonics-based approach to reading instruction, which was actually helping kids learn to read and get good scores in reading. The reason was because the teachers felt the curriculum was "colonizing" and they didn't have enough agency to determine how to introduce reading to kids. The fact that phonics has proven to be a good basis for instruction in mapping written words to sounds, even in a phonetically bizarre language like English, and everything else including "whole word" instruction and whatever learning-by-osmosis method the Oakland district ended up adopting, has produced poorer results, was irrelevant to the school board who made this decision.
Which is to me unconscionable: when it comes to education I favor whatever gets kids to learn. Especially in a place like Oakland; if you've ever been there, you'll know those kids need good education. But that's how it goes when egos, entrenched bureaucracies, and the wishful thinking of powerful people are on the line.
In an unrelated field, it also resembles the fixation the biochem community had on beta-amyloid proteins in Alzheimer's. It was an enticing theory because it seemed so simple: clear away the plaques and the brain would heal -- no more Alzheimer's! Of course it didn't work that way in reality, but it worked so well in mouse models, leading to more intense wishcasting by other researchers and on it goes.