* The human brain is not capable of evaluating and re-evaluating every possible option amongst the plethora of technical choices developers are faced with. This forces us to develop certain coarse grained mental heuristics (prejudices and biases) to navigate technology, and even if these broad generalizations are roughly true initially, we tend not to re-evaluate them over time. This leads to stale biases (e.g. some library/language was missing an API 10 years ago, and someone formed an immutable opinion on it).
* These broad generalizations lack nuance. I watched a talk recently by Dan Abramov where he calls these heuristics (I'm paraphrasing) a form of information compression [1]. That compression is lossy — it doesn't preserve the original context in which the heuristic was formed.
* There's also some insecurity at play here too. Developers want to believe that they've chosen The One True Solution, and harshly invalidating the alternatives is one way to reenforce that fantasy.
* And of course, social media has exacerbated this problem by rewarding inflammatory hot takes. You won't get nearly as many views/upvotes/likes for a sober take that says "technology X is well suited for this narrow use case" as you will for a hot take that says "why technology X failed", or "why everyone hates technology X".
You might enjoy this link: https://blog.aurynn.com/2015/12/16-contempt-culture