Prometheus
Semper Perconctor
Sorry but your conclusion isn't logical; to say that something is something until it can be proven to be something else doesn't really make sense.
By the same logic I could just as easily say "God is a giant cream filled pastry floating in the 15th demension" and, since you can't prove otherwise, claim that your lack of proof to the contrary proves I'm right.
You're right, that is entirely illogical. I point out this same example to people all the time. The difference is that I'm not claiming God is something. I'm claiming God is nothing. That is logical. Just as I claim unicorns, faeries and Santa Claus are nothing.
If you believe God exists and He doesn't, that is a false belief. A false belief is a delusion.
So I did phrase it incorrectly. God isn't a delusion, but the belief in God is.