What proof is there that it's anything else?

The fact that there is, nor ever has been, any evidence, facts or data to support the claim of the existence of any god(s), is proof enough that god(s) is a product of man's imagination.

Welcome to the asylum. Enjoy your stay.

It's been proved to be man-made, repeatedly.
The believers refuse to accept that.

Religions are organizations. Organizations are created by human beings. Not that complicated.

Everything in religion tells us it is man made. If you study the catholic church history you'll get there.

I don't think natural science can prove it but I'm hopeful that psychology will do it.

Religion is a human practice, which is man made, but religion is not belief nor faith and those who have faith may claim a 'calling' or a demand which they feel, and of which nothing (really) can be said.

I don't think so. Common sense to one person isn't the same for all of mankind.

Like whom else is in the race?

Only if you have commons sense.

We can make our own religion. That would prove it.

Religion is man made.

The idea of divinity behind those religions is a lot more troublesome as they often are too far removed from what we know as reality to conclusively disprove.

For example. I believe in 'Dave', a 3-headed giant ostrich like being existing in another dimension who created this universe when he sneezed.

Sure, it is a religion with just one follower. But prove me wrong.

Scientology

It's self evident.

Is there any way that religion can be proved not to be man-made?

Well who the hell else do you think "made" it??!!!

Preponderance of evidence. It's not proof, per se, but it sure is compelling.

Look at its history.

is there any way to prove it isn't? of course it is man-made. each one is curiously favorable to the group that has created it. there is no religion that says "the other guys is better; you're not as good; god doesn't love you as much as those other guys." not a single one. why is that? if religion is not made by man but rather created by some deity, why would that deity make so many conflicting ones, and why would s/he tell every group it is the best and everyone else sucks? (well, ALMOST every other group, anyway.) you may as well ask if we can prove santa claus is not real.

g

YES. Just look at all the different beliefs and doctrines all coming from just as many scriptures. Either religion is man made or gods (if any) do not want to communicate with us.

As opposed to naturally occurring? It can't be anything but man made, there's too many to choose from.

We will all die not knowing for sure, but objective scientific facts are as close as we can get to absolute truth.

Whether or not there are any gods, and I believe there are not, religion itself is a social construct. If there were gods, they would continue to exist even if no one worshiped them, just as people worship even though there are no gods. Religions have more or less evolved over the millennia to fit the needs of their societies, so without knowing exactly when and where the first religion started, it would be impossible to prove the origin of religion, just as it is impossible to "prove" the nonexistence of gods or other unlikely beings.