Most of their argument is an analogy. Objects don't just come into existence, some one designs and makes them.
But that analogy is too simplistic. Usually, one or a number of people "design" something ... and then still others "make it."
And so, given the VAST variety of life on earth ... it only stands to reason that there is more than one designer ... so "many Gods" or polytheism is more likely ... and the you also need those who "make" that which was designed ... which could be interpreted as many "angles" who do the biding of the many gods.
And so ... those who defend the "one Designer" view of "Intelligent Design" should be able to show how their "theory" (not religion, theory) refutes a "multi-designer" or polytheistic alternative.
Ask a creationist to provide the "scientific evidence" which supports a "one designer" theory over a "multi designer" theory, and watch their head explode!!!
The key in debating these folks is to take Evolution OFF the table. They can't really defend ID as a science, so they do little more than attack evolution. So through evolution away, and then debate the GAPS in the ID perspective.
The one above is my favorite ... it usually leaves them stuttering, and searching for a new topic of discussion, like sports or the weather.