> Teams which constantly re-prioritise items which some fake product manager came up with a few months ago is not agile.
I don't disagree with this. However,
>True agile teams never need to do backlog grooming. If a team has a backlog which is so big that it needs grooming, then they are not agile. An agile team build something, releases it to its users, and afterwards react to the immediate feedback/next important request.
This is like saying the first test should always fail because the tested code doesn't exist. While that's a good start, it usually takes a few sprints to release anything useful; especially if you have any hardware involved. Therefore, having a number of stories in a backlog really helps, especially if you do have to re-prioritize because hardware is delayed, etc.