How can freedom of belief in Islam be reconciled with the punishment for apostasy, and what is the ruling concerning one who was born a Muslim and did not learn about the ruling on apostasy until after reaching puberty?

Their statement "Islam has permitted freedom of belief" is not accurate in its absolute sense. Islam allows the People of the Book to remain in their religion with conditions, such as jizya (tribute) and not openly displaying disbelief. However, it does not accept anything from non-People of the Book except Islam. No one in the Islamic state is allowed to preach disbelief or display it openly. As for the apostate, he is not to be condoned; rather, he must be killed after being asked to repent, because he denied after knowing the truth. His killing is a preservation and safeguard for the religion.