Large groups of people independently acting in a certain way points at a reason for them doing so.
Yes. Then you look at another large group of people, who are acting in certain other ways, and then you can only deduce that the common parts of these ways have a reason.
Now the common parts are demonstrably non-existent. Large number of people think Mohammed was greatest of all prophets, and belief otherwise is seriously wrong. Another large number of people believes that Jesus was the last of the prophets - he will come back but no one else except people peddling false gods. While simultaneously believing that belief otherwise is seriously wrong. History centric religions are mostly contradict each other.
So no conclusion can be drawn from these large groups of people.