Fully agreed with Mana's opinion.
Loosy,
The donning of oxygen mask by remaining pilot in the cockpit is NOT required, if your aircraft has a quick don oxy system. Please refer to the same FAR reference section 2, part i. I very much doubt any commercial airliner that hires foreigners in China doesn't have a quick don oxy system.
I mean no disrespect here but this is yet another excellent example to showcase how silly your colleague can be in quoting something from the FAA without understanding fully and trying to ridicule the locals. IMHO, You folks have no ground to stand on this one.
Final note, if all of you are suffering that much with hatred and ungratefulness, suggest you find a better job elsewhere. If that's not an option you need to put bread on the table, learn to adapt and and contribute more humbly and positively please.