Because of two issues: Amazon lumps all similar batteries in the same bin category so any vendor selling thru Amazon gets an item pulled from that bin where all the other vendors have dumped their stock too!
2) Amazon charges a lot to sell thru their site so vendors offer items that are cheaply made but they describe it as being “top notch” best of the best” but when tested these batteries barely have enough charge to light up a single led light for 5min! Think stuff you get from Temu and not so long ago from AliExpress (they have gotten better to be honest) temu is a cesspool because they are desperate for hooking up as many repeat buyers as they can and then they will put the pressure on sellers to be more careful selling crap as the real stuff
3)sadly all electronics and power supplies are made in China so quality is all over the place, some Chinese products are of excellent quality and the price reflects that but you must do your homework