Wrong. There are actually 4 tiers. None of them mention anything about a yellow book or pink card. They are: 1. a Thai person, 2. A farang from neighbouring country, 3. A farang working on a Non Im B, and 4. a farang tourist or expat.
Sorry to read you got out of bed this morning on the wrong side! I used my Yellow book to register (easily) and receive treatment (ongoing clinic +free Covid-19 vaccines x4) at my local hospital. I have never had a Non Imm B visa. I do have a Non Imm O which allows you to work if you chose (Group 3). Group 4 is for retirees not expats, you sir are wrong. Taken from your link.....
"The fourth group consists of tourists and retirees."
https://coconuts.co/bangkok/news/dual-pricing-foreigners-legal-thai-public-hospitals/