^^^^Nikosony

Your forgetting that not everybody who is good at 'making films' are good at all aspects of film making - you may get a great camera man/ cinematographer /director/producer etc who is not very good at editing or the creativity/visualising that comes with it. To suggest that this guy is 'stealing' it to take credit is ridiculous! - He would just get credit for the editing - because that's what he would have done.
You seem to contradict yourself - because to me it looks like you are suggesting that the editing is the most important part of the film making process (I get this impression because you seem so against others editing your frottage), and yet you state that final cut is 'just another NLE' and anyone could do it - Yes I agree that FC is just another NLE but I don't think anyone could do it (at least not a good job). I take your point about 'having complete control' over it, but this guy whose offering to edit for free could work with somebody who may not be a hardcore editor to bring their ideas to life (providing he is capable!).
It's my view that it happens exactly like that in the real world - Thelma Schumacher doesn't 'steal' Martin Scorsese's work - she works with him because Scorsee is a better story teller/creator etc and she is the better editor... I think peoples non-willingness to part with their own footage based on their views that the editor is 'stealing' credit undermines the importance of everyone's else's job in the film making process.

Just my opinion - but all you have to do is look on the credits of a good film and you'll find the editor is often mentioned way after the director/producer/cinematographer/sound design etc etc - which I think goes against the idea which I think your getting at - that the editor is the be-all and end-all.