The argument, such as it is, is simply this:
CSA advertises that they are recruiting captains, and so they are, but evidently they are not recruiting captains that they intend to routinely designate as the Pilot In Command, but rather captains who will be assigned almost exclusively to relief captain duties, unless their ambition is to do a whole lot of domestic flying within China.
That is not the same gig as being hired to operate as the Pilot In Command, and those applying need to be clearly aware of that fact. Similarly, when someone comes along and says effectively, "No sweat. Even if you aren't the PIC of record you can still log all of your stick as PIC time.", those interested in the job ought to be very aware, and wary, of the rationale that underlies the logging of that time.
The only valid reference that I can find to what you're describing, at least in respect of the FARs, relates to a circumstance of two private pilots both logging time when it had been agreed in advance that one would be PIC and act as safety pilot, but that the other would concurrently be the "sole manipulator of the controls" while practising instrument flying. That's a very different situation from the typical airline operation of a heavy crew on a long haul flight where all 4 pilots (or at times 5 in our outfit) are likely to manipulate the controls at some point (and, in China, more often than one would like, at the same point!).
It isn't a matter of whether one can provide all the records to prove each entry in a logbook, or whether one can demonstrate the requisite skills in the sim. You can put whatever you like in there and if it is certified by the last carrier and accepted by the next perhaps you have no problem. But the operating assumption is that the logbook accurately reflects the position you held and the responsibilities and authorities that you exercised in the position. Handing over a logbook filled with PIC time, if you were only rarely the individual with command authority over the flights entered, is a questionable practice, and all the more so if one neglects to clarify the distinction with those making the hiring decision.
ELAC