It is important for Christians to support freedom of religion for all because within Christianity there is a belief of free will. We know not everyone will come to Christ. But forcing/not protecting all religions does not foster a world of forgiveness and truth. A lot of salvation stories come from wills who saw Christians extending love to everyone regardless of beliefs and them wondering why or how can Christianity be so different to other religions. This is also the reason the US never established a government religion even through most founding fathers were professing born again Christians. They saw that by force created tyranny and the way to a true free society you let people believe what they want and pray for their salvation and don’t stop preaching the gospel with your own freedom. This belief has kept us the most Christian nation in the world and we never told people how to believe.