It was a Party state, the USSR. To put it another way, everything there, even the state itself, was in service of the Party and its objectives. The Comunist Party of the Soviet Union (KPCC) also believed that they were superior to all other communist parties worldwide.
Therefore, it makes sense that every nation where the Communist Party was in control reported to Moscow.
With a tiny bit more autonomy in how they conducted things, all of eastern Europe's nations were nothing more than Soviet Socialist Republics. For instance, Poland's oppression was a little less severe than that of Bulgaria and East Germany, but worse than that of the USSR itself. They were nevertheless restrained from pursuing independent foreign agendas.
Things did start to loosen up once Glasnost and Perestroika got going, largely as a result of what was happening in Poland, just as they did in the USSR itself. This gave rise to movements that eventually led to true independence for the satellite states, the three annexed Baltic States, and many of the former Soviet Union's constituent Republics.
Albania, Yugoslavia, and Romania were the exceptions to the norm, all of which split with the Soviet Union and got away with it. Yugoslavia and Romania first saw themselves as Non Aligned, whereas Albania initially sided with China. Despite the separation with the USSR, all three still operated as authoritarian police regimes, although Gorbachev's reforms also had an impact outside of their boundaries.
