> The point system is there to give an idea of how much you can cram before the deadline and negotiate with the client about what to axe from the release

Well, it's more than that though - otherwise you'd just assign each developer 80 "points" worth of work for each two-week sprint.

> If nothing is going to be cut from the requirement docs, all the castle about poibts priority and speed just falls down (or you have a ridicolously lax deadline, of the likes I’ve never seen in practice)

Adding stories to an iteration in progress is also (I'm pretty certain) explicitly discouraged.

If your manager is doing that, you've already kinda lost the Agile battle.

I think that's sorta what people mean when they say people are doing Agile wrong - they do these things that are explicitly discouraged.

Whether there's any way to reconcile that, I can't say.