The idea that ancient gods were in fact extraterrestrials, while not exactly old, is rapidly picking up steam (I've seen the mentioned documentaries a bunch on history lately) lately. I'm actually a little surprised people haven't encountered it yet. I would say that the issue isn't so much that the evidence is circumstantial, as non-existent. It's a very interesting theory, and a relevant question to ask. But every bit of evidence used to support the theory could just as easily be explained by more traditional theories (either that the gods were real, or that they were not, but we thought they were). To me the whole idea seems no more or less fantastical than any other explanation.
The assertion that we should worship god is based on the assumption that doing so is in our best interest, either because we will be punished for not doing so, or because doing so will improve the quality of life for everyone, ourselves included. If, like me, neither of these make a whole lot of sense to you (i am personally skeptical that god is on our side, if he exists) than the whole argument goes out the window, and i would recommend giving this question up for awhile. That is (as far as i can tell, it is hopefully clear that im no theologian) the ultimate justification for surrendering to god.