What we call "religious persecution" was done by absolutely everyone everywhere in the world until about the 18th century (and even then, it was only in the 20th century that the majority of countries stopped doing it).

This is because all adherents of all religions agreed that it was a matter of public interest to ensure that the right gods were worshiped, and worshiped properly. If your city didn't worship the right gods, or didn't worship them correctly, they might decide to smite your city. To allow your neighbor religious freedom seemed as absurd as allowing your neighbor to set his house on fire - the fire might spread to your house, so you can't do that.

The modern idea of religious freedom only became conceivable once people basically stopped believing that God or the gods intervened in the world very much. That's why the first supporters of religious freedom were Deists (people who believed in a distant, non-interventionist God).