Answer:
Because their governments were puppet governments of the Soviet Union. They revolted to gain democratic values and many even left their countries to get to western Europe.
Step-by-step explanation:
The Eastern Bloc, also known as the Communist Bloc, the Socialist Bloc and the Soviet Bloc, was the group of socialist states of Central and Eastern Europe, East Asia, and Southeast Asia under the influence of the Soviet Union that existed during the Cold War in opposition to the capitalist Western Bloc.