Checking on arrival in Bangkok does not sound right. Like they do with visa, it is probably the airlines resonsibility to check you only fly with a negative Covid test. If they let you board the plane without, the airline also has to pay for your return because they do not let you into Thailand.
There was no question, and the OP was the one doing the venting. Complaining about Thai immigration is proof of not having a constructing live, as it is useless.
They do not need well trained staff that see tourists as customers. People wanted to come here without that. Apparantly 150,000 are still working every angle to be able to stay here, the promised land. Why would they change?
Every immigration office makes you jump through hoops. It is part of protocol.