Many religious believers try to frame debates in a way that makes it seem like they represent an overwhelming religious consensus – one that is being challenged by a minority of nonbelievers. At best, this would be no more than an Argument From Popular Belief, but you should challenge this very assertion by pointing out that different religions makes wildly different and mutually exclusive claims, which means they cannot be lumped together into one cohesive category. At this point, some religious counterparts will make the claim that what’s true for one religion is not necessarily true for another – that religions might be very different, but that they’re all equally true in their different ways.
There is a big logical problem with this, though:
Different ideas can, and often are, believed to be true by different people, but all this shows is that different people have different subjective feelings about things. The logical mistake here doesn’t come from the fact that people vary in their subjective beliefs, it’s that these conflicting subjective beliefs can somehow be objectively true.
A clear example of this is the Christian claim that Jesus was the son of god/god himself, who died on the cross to atone for mankind’s sins, the Muslim claim that that Jesus was no more than a human prophet who did NOT even die on the cross, and the Jewish claim that Jesus was just a heretical Jew. These are three very different and mutually exclusive ideas that cannot all be true. You can indeed claim that three people can each subjectively believe different ideas, but you cannot claim that all three ideas are objectively true. And to claim that they can be objectively true depending on who you ask is no more than a Relativist fallacy. The flat earth and the round earth ideas could not be both objectively true, and the geocentric theory and the heliocentric theory could also not both be true. Different things can be subjectively believed, but objective truth is a singular thing that does not depend on people’s beliefs. The logical thing to do, therefore, is to base your beliefs on objective reality, not the other way around.
With this in mind, it actually turns out that there is no such thing as a religious majority or consensus. Every religion represents a minority opinion that disagrees with other minority opinions.