There's a gigantic organization. It has connections to natural resources, contacts with traders and political leaders, and has an armed force. There's an opportunity to get your family/clan/town/region access to those resources, people, and arms. That same opportunity is probably being offered to rivals.

Enthusiastic embrace is the most logical option in a lot of situations.

Any of them. They're all former pieces of the Roman empire. There isn't any rulebook declaring what is and isn't authentically Roman.

The line between norms/customs and legislation/policy is very thin in some parts of the UK government. Monarchs have tried to expand their own power and it isn't successful in history. Though yes, you could technically call it a theocracy now, though it impacts governance less than the term might imply.

'Civilization" and "height" were bad choices of words by the article IMO. Maya is more of an ethnicity than a social structure.