It was an attempt of the Polish resistance to avoid being "liberated" by the Soviets to just immediately become occupied by the communist red army. The idea being to liberate Warsaw and get US/UK assistance through the Polish government-in-exile in London to establish Polish military control before the Soviet army arrived. Getting US/UK support could have meant that Poland remained an independent state. Instead, Stalin not only betrayed them, but later actually convicted the surviving leaders of the uprising. "Crimes against communism".

This is now politely referred to as a Soviet betrayal in service of "Stalin's post-war political goals for Poland".