Your point seems to be the westerners need to make their own research and understand the landscape when signing with such agencies / operators. And so do the easterners, no difference. It is the same landscape introduced to the EU by RYR and their US owners 2 decades ago. BTW those agencies are predominantly British Commonwealth registered entities, it does not get much closer to CAA UK than Crawley.
When I see a contracted offer, clearly my take home is (after direct expenses) 25%-35% less and I need to register a proper business structure in my tax residence country.
About the advertisement, true. But hey EK also boast 42 days of annual vacation, Qatar tell you there is a contract. We could go on for pages with those examples. My recent favourite is the HNA group (China, about 8 expat-ready airlines in total) 'grounding insurance' for lost medical only pays out after you regain the CAAC Class 1, ... imagine the no pressure on the doctor from the company there.
The contract never says it is tax-free money, it says proper taxation is the supplier's sole responsibility.
It is very helpful you brought that up. My case about the previous vile rant not being attached to any part of reality is put to rest.