How many times did this happened in the OT:
Israel was occupied because they turned away from God. Then a chosen one liberated them. Then they turned away from God again, you know the drill.
The Jews were persecuted because they kept on rejecting false religions and false prophets. From the ancient Egyptians, Romans, Christians and Muslims, have tried to impose their version of god or gods on the Jews and the Jews rejected those attempts and suffered enormous persecutions as a result. The Jews did not stray from their God. They kept the covenant with their God since the days of Moses.