Re: In Ha Noi the city government often simply takes the land and pays compensation
That happens in every country. Each country has its own legal procedure, and maybe in Vietnam it is slightly easier or appears to be more of a one-sided decision, but there is no country that does not give itself the right to appropriate private property.
The only question is how justified does that right need to be. Given that you mention that some Vietnamese can block such a decision, that tells me that the procedure in Vietnam is not so different than in many other countries.