Why are the chances of entering Paradise greater for those born to Muslim parents than for those born to non-Muslim parents, despite Allah’s absolute justice?

Allah Almighty does not punish anyone except after establishing the proof against them by sending messengers and the message reaching them. As for those whom the correct message of Islam did not reach, and who did not hear about the Prophet, peace be upon him, the preponderant opinion is that they will be tested on the Day of Resurrection. Justice is established among people, and Allah Almighty has guided all people to the two paths (good and evil), and has granted them the ability and will to acquire their deeds. Therefore, you find those who apostatize from their religion and those who embrace Islam and perfect their Islam. The probability of guidance and steadfastness is higher for those found in Muslim lands or born to Muslim parents, and this is Allah's favor which He bestows upon whom He wills. "Indeed, you do not guide whom you like, but Allah guides whom He wills. And He is most knowing of the [rightly] guided" (Al-Qasas: 56). So, guidance is in the hand of Allah alone, and He knows best who is fit for it.