Why did God not protect the Kaaba from the Qarmatian attack, and why did He not punish their leader, Abu Tahir, if Islam is the true religion?

The memorizer Ibn Kathir answered a question about why the Qarmatians were not immediately punished like the People of the Elephant. He explained that the People of the Elephant were punished to demonstrate the sanctity of the Sacred House before the Prophet's mission, lest people deny its virtue if they were to seize it. As for the Qarmatians, they did what they did after the laws were established and people knew of Makkah's sanctity. Therefore, there was no need for their immediate punishment; rather, Allah delayed them until a day when eyes will stare fixedly, in fulfillment of His saying: "And never think that Allah is unaware of what the wrongdoers do. He only delays them for a Day when eyes will stare [in horror]" (Quran 14:42), and the Prophet, peace and blessings be upon him, said: "Indeed, Allah grants respite to the oppressor, but once He seizes him, He will not let him go."