ID doesn't say a god, as defined by earth's religions, is responsible for the existence of life on this planet. It simply says that an intelligence was behind life being on this planet. That could be ET's uncles and cousins for all we know. The point is that the complexity of life on the earth and the amount of time allowed (roughly 5 billion years) contradict a theory of gradual change and development.
Perhaps there's another planet out there someplace where "life" originated and this life is the source of other life in the universe. Perhaps, if we were on that planet a naturalistic explanation for the origin of life would be much more obvious than it is here on earth.
The point is this. Intelligent design doesn't necessarily mean a god. Like in the second or third "Star Trek" movie, it could be some kind of "genesis project" carried on by extra-terrestrial, intelligent beings.
Actually, ID's founders really weren't interested in "creationsism." Creationists have seized upon ID because it assists their arguments. To fault ID for that is a bit like faulting medical advancement because religious hospitals use newly devised treatments.
ID uses a different method for criticizing current evolutionary theory. It uses mathematical modeling. According to this modeling based on information theory and only possible because of the advent of computers and their ability to crunch huge numbers, the probability of such a complex system is impossible given the amount of time available. Modeling is now used in every field from aerodynamics to quantum physics. If we're told there's a mathematical problem, then I'm an adult, I can handle it.
Do you believe that other intelligent life exists in the universe? Given the vast numbers of stars, planets, etc., there is a likelihood that other intelligent life exists out there. We won't go into UFO sightings and all the discussion in that area. But it's a valid discussion.
What's wrong with the notion that a more advanced civilization has "seeded" this planet? That accomodates the ID model and it recognizes that the origin of intelligent life could have an easy explanation elsewhere in the universe that we're simply not seeing yet.
Attempting to model evolution without understanding any of the basic biology is the fault that plagues Dembski, Behe, and the rest of the ID crowd. Math is just the language; without factual content these folks are just babbling and their probability estimates are worthless.
For example, these fellows could use a supercomputer with the help of most accomplished mathematicians available on the planet and they still couldn't successfully model the Wright's first airplane. In all likelihood they would finish their model, run the simulation, and proudly announce that heavier-than-air flight was an impossibility. A fresh engineering school graduate with single course in aeronautics could have helped them create a proper model. They have assiduously avoided the kind of information that a microbiologist could have provided to correct their "information theory" model of biological evolution.