"None of these are arguments from incredulity." - Earnest
Really? OK well let's apply your reasoning to this:
"Assuming that the universe was not wished into existence by a Genie is an argument from incredulity" - Me
"Also, creationists find it difficult to believe (i.e. are incredulous) that the apparent perfection of organisms is not evidence of a Supreme Designer, and so they assume there is a designer" - You
Also, people find it difficult to believe (i.e. are incredulous) that the apparent wondrous nature of the universe is not evidence of a Genie wishing the universe into being, and so they assume there is a Genie behind it all.
Also, Lasthursdayists find it difficult to believe (i.e. are incredulous) that the universe has existed for so long, and so they assume everything was created last Thursday.
Longs story short Earnest, if you buy into the nonsense spouted by these creationists and you repeat it then you will make yourself look silly.