Irreducible complexity- the challenges have been rebutted (if not refuted)

Note from a pedant:Technically, it's the 'Argument from Personal Incredulity' that is a logical fallacy. In other words where the argument simply consists of 'that sounds absurd to me', there is a logically valid from of the 'Argument from Incredulity' where one supports the argument with evidence for the event(s) in question being fantastically unlikely.

You are right, it is unscientific. To be scientific we require evidence, and testable hypothesises. This is neither. Nor is it any kind of evidence for evolution. What it is though, is a demonstration that a spider web is not irreducibly complex, and an elegant one at that. Therefore any argument against evolution based on spiders webs being too complicated to evolve is refutted.You're earlier description of the evolution of spinnerettes however is a testable hypothesis. If it is true then the spinnerettes will be expressed by the same part of the genome as codes for their analogues in King Crabs.