There's a very reasonable argument sometimes made that even if we entertained the idea that life on Earth was "intelligently created", we would have to first rule out natural causes for that before jumping to the conclusion that it must have been a god. The most obvious natural cause for it would be if an alien species from somewhere else had planted life on Earth.
So far there's little reason to believe that life on Earth was caused by an intelligent being or beings, as the vast majority of phenomena causing the diversity of life can be explained by the laws of physics. But as said, even if we did consider the possibility, jumping to a supernatural god is not the only choice, nor is it the most reasonable choice. Before even considering such supernatural explanations (and especially before considering it the most likely explanation), all the natural explanations (such as aliens) should be completely ruled out.
A more fundamental point that this argument is trying to make is that even if the appearance of life on Earth couldn't be explained by simple natural processes, a god is not the only possible explanation. There are other alternatives as well.
But of course creationists, the dishonest liars they are, love to distort this argument and build a straw man out of it. They like to spout things like "Dawkins considers aliens to have created life on Earth", completely (and probably deliberately) missing the point. Basically what they are wanting to say is "ha ha, those silly atheists, they think that aliens created life on Earth! How crazy is that?"
But what else can you expect from such dishonest hypocrites as creationists?