I think this is a great question. It is important that Christians stand up for religious freedom of people of all faiths because freedom to express our thoughts and live our life is a part of the human experience. We should have the freedom to worship, share our faith to those who are willing to listen, and gather. Even if we disagree on certain things, it is important to cultivate a society that is not afraid of ideas that conflict with their own. I think the reason many Christian (myself included) may shy away from standing up for religious freedom is fear that standing up for their freedom means we are not standing true to what we believe. Two things can be true at the same time. Standing up for people to have religious freedom is not in contrast with having a different faith than that group.
I also think having some form of religious belief is good for society. When people are blinded by a common faith, they tend to be more family-oriented and children thrive off of a strong family. No one is perfect, but when religion is done correctly, it can have great benefits for people all around.