1) They tell us that Quality Assurance is what they do, Quality Control is the rest of us making sure that we've done everything properly in the first place - this has been the viewpoint of most QA departments I've encountered in 26 years of plane mending.
2) It stands its ground - bravo!
3) Yes, when he is right, or if he's made an error that was not intentional or malicious.
4) Referring to 1) they don't impose, just keep an eye on us.
5) Not me.
6) See 5).
Polite enough?