Why is it so hard to get clear requirements for tasks?

No matter how long I've worked as a software developer, I still feel like 90% of the battle is even having what I'm supposed to do. No matter how much companies brag about "oh we're agile this" or "oh we sprint this sprint that", I still feel like there is never any consistency with project managers, business analysts, etc. when it comes to writing ticket requirements in a parsable Given When Then style format. It seems like its only my friends in the so called "FAANG" companies that have any kind of consistency with this.

It feels like being a developer involves giving yourself some kind of adult ADHD where you have to have a million tabs open, constantly interrogate the non developer staff who you'd think would have the sole job of getting this all together, and then the whole burden of figuring out what is needed or should be done seems to fall on the back of the principal/lead whatever engineer who just works absurd hours.

Anyone else able to relate to this?