To be fair, even though not especially well written the article does seem to be referring to a specific add “The ad appeared on the website of a car rental company”. And says immigration counters do not offer that service which is true. That does not mean that there are not legitimate companies offering the service, and it’s not just immigration fast track it’s also security. I personally get it through my Citibank credit card and it’s indispensable, taxi to lounge in 5-10 minutes usually. I believe there are two fast tracks. One is VIP, first class and air crew near Gate 1 and the Thai checkin, this is what Citibank use and is great. the other is in between the two regular lines last I saw, think elderly and and others with disabilities can use it and maybe some airlines offer it with their first/business class seats. Looked very hit and miss when I passed