The hotel guest works as a teacher in Thailand.

Then his freedom and his livelihood suggests he should maintain a low profile. Right or wrong, he's not in America, and shouldn't behave as though he is.

Make it anonymous.

Kinda hard to do, if you complain about unique circumstances at a specific location

You at least will have some leverage and the ability to deny

The screenshots that the hotel provided show that he made multiple Google accounts with his real name to repost the review.

Perhaps this is an effect of a new rise in "local tourism" necessitated by Covid-19. Locals reviewing tourism industry businesses instead of international tourists.

And don't go back

yeah, at the very least you won't get spit in your food