I agree it's probably a bit of everything. Some of those offers (links removed now) were from lowcost airlines which notoriously offer low salaries, but there are even 3 chineese airlines offering packages in the region of 20000$ and above with commuting and one was even for long haul, how come they don't get enough applicants?
I haven't been there myself but hearing from colleagues:
The medical, bureaucracy, hygiene, pollution, culture, safety, CRM, contracts not being respected, language barrier, distance to go home etc.