The first problem ID’ers have is their inability to comprehend the immensity of time. They look at life around them in the small context of their existence.
The human intellect and its introspective nature is a relatively late development. Intellect has always evolved with organisms but its sudden encounter with the exquisite machine of the human body causes problems of reconciliation.
This may be the clue to the perplexity. When the recent intellect ponders the ancient body it is amazed.
Imagine a universal lottery with odds of winning of one octillion to one. If you bought a ticket you could just as well admit your loss right off the bat. But someone in the lottery will win. It is guaranteed. From one perspective winning is absurd, but from the other it is an absolute certainty.
When opportunities for an unlikely event approach infinity the event becomes nearer a mathematical certainty.
Amazement at our situation is not a reason to doubt a natural provenance.
The human intellect is like a babboon riding around in a Ferrari.
Why would any Cosmic Engineer design something so complicated so it could run around a trailer park in a wife-beater with Cops on its tail.
The truth is that there are far too many flaws in organic beings. Anything capable of that level of engineering would not have been subject to making obvious mistakes.
Mechanical devices and organic systems are too dissimilar in process to be analogous. Our inventiveness does not imply our invention.