Thailand has cycled between elected government and military dictatorship something like 15 times while he was King, the miracle is he didn't have an outright civil war during his reign. If you've ever visited Thailand, you'd know that compared to surrounding countries (with the exception of Malysia perhaps) the level of infrastructure and standard of living is much higher in Thailand, things generally work there whereas in neighbouring countries like Cambodia/Laos/Burma they generally don't, or at least they haven't until very recently.

To at least my outside perspective, The King seems to have been a stabilising force which prevented Thailand from descending into outright civil war.

And I can't help but feel that somehow insinuating that America shouldn't consider Thailand an ally after the events you listed is a bit ridiculous considering the year before they occured the US was still in Vietnam fighting a war with allies who were torturing and killing a damned site more people than what was happening in Thailand around the same time.