Religions are mutually exclusive by their own doctrine. The major religions have prohibitions against each other written into their doctrine. So if any particular religion is in power they will naturally discriminate against non members.
And this even goes down to the sectarian level. As we can see all too well in the middle east. It’s not even different religions fighting each other. It’s different sects of the same religion. Their hatred of each other is a result of official doctrine. So as long as one of the groups is in power it will be at the expense of another.
The only way to break this cycle is to have a government that is religiously neutral. Some Europe countries are the closest the world has come to a religiously neutral government. Even the United States government is being tied up in knots because of religion. Though that is a battle between Christians and the non religious.
Religions naturally want to impose their will on everyone else. This is a constant and re occurring source conflict. Only when religions are kept out of politics and power will they be able to peacefully coexist.