Because they hate the idea of independent nations. They want a One World Order where we all live and operate under the same rules.
A large part of this is based on jealousy. Many,MANY people can't stand the idea of anyone else having a better house,better job,more money,more toys,etc,etc,etc. Under communism,everybody has what they are ALLOWED to have,nothing more. Seems like there are many people who are willing to live with less as long as no one else has more.
Except for our masters,of course. SUMBODIE has to have the whips and chains to keep the other beaten peons beaten into line.