The truth that people don't want to accept is that Cream completely ruined Amy's character

Amy was consistent between Sonic CD up until SA2. The moment Cream was introduced is when Amy went from a sweet delicate girl who wants to protect others to an angry weirdo completely obsessed with Sonic for comedic purposes. And it's all Cream's fault since she was created to be Amy's sidekick, and they needed to establish a dynamic with the two. So they gave Amy's previous delicate traits to Cream and made Amy easily irritable and irrational, something that simply wasn't present in pre Sonic Battle games

Now some people will defend Amy in stuff like X, Battle and Rush, by claiming that during this time she was going through a character arc and getting physically stronger. But Amy's abilities during this time period are nothing but a shoehorned attempt at making her capable, since she isn't special when compared to the other animal characters as she wasn't originally designed with gameplay in mind. Giving her a hammer was a good idea, as it could serve as a way to make Amy compensate for her shortcomings and make her more unique compared to the other characters that have natural abilities. But you can't simply make her considerably stronger than most other characters and explain it away through some "training hard" bullshit. And making Amy strong ultimately contributed to her negative perception of being an angry spaz, as by that point Amy's delicate nature was pretty much gone and given to Cream

Even after Cream was considered a flop and shelved up until recently, Amy was still portrayed as easily irritable in Sonic Riders and subsequent entries. It's no wonder why people hated Amy back in the 2000s. Sure, American fans were already iffy on the character since SA1 as some felt she was "replacing" Sally, but the hatred towards her really only started to pick around 2004 onwards. And it makes sense because 2000s Amy basically was an in universe lolcow