I had a conversation with my wife about this just about a week ago. We have a different background (America vs Europe, me being Europe). When she explained “Quiet quitting” to me, my reaction was the same as yours. Quiet Quitting is just doing the job which you are paid for. Which to me is perfectly reasonable.

Culture probably plays a role here. Like that joke about an American making calls / texting for work while in the hospital, and a European taking 4 weeks vacation for the summer, just dropping everything work related.