It is best for casinos to clearly state their stand on the regional restrictions so that visitors can see for themselves before registering so that they do not blame anybody it they go against the ToS.
Valid reasoning. Logically, gamblers wouldn't be able to access the site if their country was restricted, but such lists are essential for clearing up any confusion completely.
I believe most times casinos intentionally do that upon launch to allow traffic to flow in and when they start getting the traffic they desire, they update their terms of service and registered members would not know that until they want to make a withdrawal and the casino requests for kyc and then they would tell them that their country is on the restricted list and would get their account banned or suspended after they had deposited funds to play and won games. There was a time on this platform when cases of this nature were reported here and from findings, most of them were innocent as the casinos initially did not state their restricted nations and kyc as well but after a while, they secretly included it and did not inform their members using the claws of they changing their ToS on a discrete condition without the consent of the gamblers which the gamblers have accepted before signing on their casino.