I hope I spelt that right.
But why do they always have to be?
Maybe they are kind of neutral.
I don't think that a god would necessarily have to be benevolent. In fact, some conceptions of deities, even the most widespread ones, have been downright malicious.
That being said, if there exists a god or gods, I find it highly unlikely that it/they would be malevolent. Generally speaking, as one becomes more wise, they have less reason to be malevolent. I'd imagine that a being that is far more powerful, old, wise, and knowledgeable than a human would have little reason to be evil.
I think neutral would be a rather appropriate position of a god. I mean, if we're talking some monotheist type god here, or some pantheon of gods, I don't see why they'd care about humans any more than we care about ants. They might not even keep track of every planet that has life on it, who knows?
A benevolent god is possible, I suppose. If a god's primary passion is to create things, it might as well want to be good at what it does and create happy things. And then of course there are conceptions of gods that include all things, in oneness, so self-interest should dictate that it would at least try to be neutral or benevolent.
But looking at nature, my guess would either be that there are no gods, or that if there is something resembling a god, it is rather neutral. One need only look at the universe and its properties to discern at least some basic ideas of what such a designer may be like. The laws of physics follow cold, hard math. If a planet is in the way of an asteroid, then so be it. If an antelope can't outrun a cheetah, then it dies a brutal death. If that cheetah can't catch the antelope, then it and its little cubs starve to death. But then of course there are things like strawberries and xboxes so it's not all bad. =/
-Lyn