If the crew had told ATC twice that it was commercial reasons, I cant understand why he should have expected the crew to elaborate any further.
However I also agree that the crew should not have done anything without clearance. Perhaps the language barrier was playing its part.
That is why the original story doesnt quite add up to me. I certainly cant think of any reason to divert to ALC for technical reasons at that point. I would suggest the crew gave that answer to try and expedite reclearance.
I apologise if I offended any ATC friends with my 'nosey' comment. Surely as long as the reason isnt an emergency or technical, what difference does it make? Can you file a plan for an in flight diversion?