Because ID and SETI are exactly the mathematics. However, for SETI, organization in a much simplier “radio wave” is an AUTOMATIC indication of design; yet there is NO acceptable level of organization (complexity) within any living body for which the evolutionist would be willing to apply Probability Theory.
In other words, Probability Theory will NEVER be allowed to be applied to any component of a living organism, no matter how complex the design, because they all know that life DESIGNED itself through evolution. Therefore, how could any of these scientists make the argument that probability theory is to be applied to radio waves (in ordered signals), but can NEVER to life itself.
In other words, if you believe life designed itself, why couldn’t an radio wave also have designed itself or have become ordered when it passed through such-and-such or because of mother nature or whatever?
Your definition of an evolutionist is little to narrow for me. Probability theory can be applied to an organism as long as there is some positive probability that the theory can be falsified. I might, for example, construct a theory that all humans are born with two arms and two legs, which is normally the case. Sadly, however, there are times when the theory breaks and the hypothesis is falsified. In my mind, therefore, I could be an evolutionist but still subscribe to probability theory.