No it's the consequence of local politics always making it easier to put additional requirements on foreigners to be seen as taking tough measures. Thailand isn't alone on this. Most countries are guilty of excessive scapegoating of travel. There's no more sense to testing a recent arrival 5 days after they've already had 2 negative tests than there is anyone else in the community. The people doing PCR tests have built up a very lucrative business and some hotels are reportedly scamming people with forced quarantine.