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?
Another thing that I find surprising is that 2 of those offer are from lufthansa group airlines, I thought the union was very strong there and would prevent things like this...