Are aliens not logical?

Rating: 1/10 (20 March 2006)

The biggest problem that I had against this movie was the logic. Why would aliens attack a planet that precipitates water and is 75% covered in water if they are allergic to water? Personally, I think that if they are supposed to be far more sophisticated than us, they wouldn't come near our planet.
The other biggest problem that I had with Signs is the fact that scientists believe that no life can live without water, so according to that theory, these aliens shouldn't even exist.
In my opinion, the writers should have thought of something else that would kill the aliens off... maybe some other common household item.