We know and can prove that man creates gods: we've created them thousands of times, all over the planet. However, the opposite is not knowable or provable. There's no reason to inject the supernatural into reality: but if you insist, then the proposition that God created man is, at best, pure conjecture – NOBODY knows anything about the supernatural. Period. Never have and never will. Anybody who claims otherwise is lying or delusional. That’s a fact.
The fact that man has created countless gods, from time immemorial, is very compromising to believers; so they do their best to forget this truth. Without reason, they assert that the gods and religions that came before and after their own are false – but theirs is real and true. Maintaining the falsehood of those thousands of other gods and religions – while claiming the truth of their own – is patently and transparently ridiculous. Sorry, believers: there’s no way to present the truth without offending you. Your assertion that your god is the one and only, true, God, is an extraordinary claim. Extraordinary claims require extraordinary evidence. But I’ll let you off the hook . . . just present ANY direct evidence for your conspicuously absent God and I’ll be the first to worship Him.
There are a myriad of arguments for or against God. There's no direct evidence for God but we definitely know that men create gods. To me, it's necessary to define what you mean by "God" to begin with. For most of us, that means a God defined by a religion.
And that's where the problems start . . . at least for the Abrahamic religions (Judaism, Christianity and Islam). Any mention of "religion", below, refers to "Abrahamic religion" for short.
Religions are born into enmity because they try to lay claim to God. This insistence on exclusivity sets up religions for contention. Christians and Jews, certain of their respective righteousness, await the end-time when God will finally eliminate their “competition”. Muslims believe Allah awaits the final “umma” -- the day when the entire world is united in Islam. There will be nobody left without the shahadah ("I testify that there is no god but Allah, and Muhammad is his Prophet”) on his lips. The final umma is the Muslim notion of peace: but they have to convert or eliminate nonbelievers (by any means) to achieve it. That’s the ultimate goal of jihad and the responsibility of every Muslim.
It's a forgone conclusion that no single religion (much less, denomination!) will win the world on its own. After all, they've had between 1,400 and 3,500 years (Islam and Judaism, respectively) to do so and haven't made any real progress. Christianity, with over 2 billion adherents, leads the pack but Islam, at 1.3 billion, is coming on strong (again). Despite being many centuries older than Christianity or Islam, Judaism has only 14 million adherents. Unlike Christianity and Islam, Judaism has no missionaries. They don’t proselytize or recruit converts. Muslims don’t hate Jews because Judaism threatens their religion: they hate Jews because Muhammad, in the Qur’an, taught them to. Many Christians have blamed Jews for killing Jesus, despite the fact that the crucifixion of Jesus was (allegedly) the divine will of God. God’s Chosen Ones have been persecuted from the beginning and it doesn’t look like that will change anytime soon.
Given all this . . . how are we supposed to decide which religion, if any, is right? The first one? The strongest one? The biggest one? The most sophisticated one? The most realistic one? The competition reduces our choice to a roll of the dice. And why would we go to hell for guessing the wrong one? It's ridiculous. Can God really be so sadistic? And if so, why would you worship him?
No . . .
NO religion can be valid if God exists AND is good. Any entity who could create the universe, would not be so petty as to set up his "intelligent" beings for condemnation. Why would the Creator give us a choice, only to confuse the choice of Creator? I say that if God exists, ALL religions are heretical. If God is good, we wouldn't be killing each other in His name. In the paraphrased words of Stephen Roberts:
"I contend that we are both anti-religion. I just believe in one fewer religion than you do. When you understand why you dismiss all the other possible religions, you will understand why I dismiss yours."