For real. All the stuff that person complained about is something a manager should be handling. Mine do. It's very rare for requirements to change for things I'm working on. There's typically going to be some small changes, e.g. wording of a message or moving things around in the UI, that happen but that's to be expected and one of the better parts of working in agile. You make something and find it doesn't work as well as you hoped? Tweak it.

I think the only time things can change drastically is when I'm working on a priority event, AKA something really bad happened for a customer and we've got to fix it ASAP. There's no time to do in depth research beforehand. You just dive in and sometimes you think it's one thing but it's really something else or it's just more involved than you thought.