"All gods are man-made."
Do you agree with this statement?
Yes, I think so.
If you do, how do you support it, what evidence can you provide for it?
I guess to start off, there's the word 'god(s)'.
That isn't very informative, so the meaning of the word needs to be fleshed out descriptively or doctrinally. That's usually done in terms of one of the theistic religious traditions.
Then there's the question of whether anything beyond human beings' imaginations actually corresponds to the word. We might ask whether anything satisfies the traditional description. Or, if conceivably nothing does, we can still inquire into whether word reference might be fixed in some other way. (Perhaps ostensively, as the perhaps-indescribable object of religious experience.)
Now addressing your question more directly, in light of what I just wrote, I'll suggest that traditional descriptions of and doctrines about god(s) seem to me to be very contextual, very reflective of the cultures in which they appear. For example, the Quranic accounts of Allah present a deity that seems to me to illustrate a Semitic tribal chieftain on a cosmic scale. We see pretty much the same thing, in earlier form, in the Hebrew scriptures. Meanwhile in India, we find gods that seem very illustrative of the social mores and worldviews of ancient and medieval Indian cultures. In China, the gods seem peculiarly Chinese.
That doesn't necessarily prove that the various culturally-specific accounts of god(s) are purely the products of cultural imagination and lack any further reference. It's hypothetically conceivable that some of these authors really did encounter some kind of supernatural being(s), and that later tradition then proceeded to dress it up and embellish it in terms of the conceptual vocabularies with which people in the authors' time and place understood such things.
So the question then seems to be, is there any convincing reason to think that that's the case. Is there reason to believe that any of these accounts or descriptions, however culturally contextual the imagery and concepts in which they are expressed, really do point beyond themselves, to something that isn't just another idea from that culture?
And that more properly epistemological question in turn raises all kinds of new problems about the evidenciary value of tales of miracles and wonders (and the Humean-style rejoinders to them), the evidenciary value of religious experience, and so on.
I guess that my own view of all that stuff is that the argument from religious experience might be the best of a weak lot, but at best, that kind of evidence is only going to be accessible to the individual having the experience. And there's still the familiar problem that schizophrenics also enjoy experiences that they find totally convincing. So something else still seems to be required in order to distinguish between veridicial uniquely-personal experiences and simple delusions.