In the words of Sandra Day O'Connor "I know it when I see it." The problem you've highlighted with defining what porn is is not a new debate and as you've admi

In the words of Sandra Day O'Connor "I know it when I see it." The problem you've highlighted with defining what porn is is not a new debate and as you've admitted we'd be here all day - and likely still not agree on a definition. The problem with your definition is that what people find arousing is a pretty wide spectrum and would include things that are not traditionally regarded as porn. Going back to our thought experiment, at what point would my theoretical graphic memoir of Riley Reid no longer be porn? What would the words to picture ratio have to be? You can make this same argument about Gender Queer; does the inclusion of the illustrations add any significant value to a memoir about someone discovering their identity? As far as whats appropriate for minors in a public school setting, society decided a while ago that once sexually explicit material is included, there is no countervailing interest. This is a pretty black and white standard that until recently all parties found agreeable. If you are advocating for changing that standard, you'll have to defend why children/teens/minors have more of an interest in seeing illustrations of a minor boy performing oral sex on another minor boy than seeing an adult woman in the nude. Claiming it not being porn can be argued both ways for both.