"why maintain citizenship"
In fact I live in the US but haven't applied for US citizenship for this, among other, reasons("passport" being woefully misused word in this context). Anyway, that is a very poor advice since:
1. Most people have one citizenship, including expats (most return).
2. Giving up your US citizenship implies very many more things than not paying taxes. Look up ex-pat type laws.
"American passport does provide you with services" Well the passport surely doesn't. The citizenship might, but I've been an expat all of my life (started bouncing around the world at the tender age of three weeks). I've never used, no one in my family has every used, an no one I know has ever used our rich, Western countries' services [0]
I have used the services of the local police very many times.
"No, it's a safety measure"
The Special Forces aren't on a razor's edge ready to jump and come get you. That's BS from Hollywood. You get in trouble abroad, and yes, you can ask for the local consulate to send someone to see you in jail. That's, in the vast majority of cases, about it. But I try to avoid jail myself.
[0] We're not British. Apparently, Brits get into so much trouble abroad that the Brits have come up with a simple solution: charge the drunk louts for consular services!
EDIT: To be clear, when I move to another country, I take pains to declare that I'm no longer a resident lest I continue being eligible for that country's services.