Actually, the only thing I said was that there is a legitimate debate as to whether a clear difference can be drawn between "Porter" and "Stout". I think there is, and that debate has been worn to shreds. Those on either side have brought BJCP into the debate in one way or another, but few would suggest that BJCP provides a final answer to this interesting question.
I am familiar with the guidelines and the difference between a category and a style, but I'm not at all sure how that bears on my suggestion that to simply state "I know the difference between a porter and a stout" begs an interesting question. Doc, I wasn't asking for, or providing, an answer. I was pointing to a question. My opinion? For what it's worth? The lines between "Porter" and "Stout" have become so blurred as to become essentially indiscernible. But I won't argue that... I'm not knowledgeable enough. Again... check my posts. No answer... just pointing to a question.
Now, as to interesting questions: Interesting questions get more interesting, not as people advance answers, but as they advance the question. That is, the question becomes polished and refined and becomes more enlightening and more interesting. We are, of course, tempted to say "That question is dead! Answered! (BJCP, Jamil, Palmer, your god here) said so! Look here!" That's not interesting, unless you're talking about a question like "is the world round or flat?" It's an almost religious approach ("The God in whom I trust has spoken.) The question as to the difference(s), if any, between a porter and a stout, is, I would hope you'd agree, not a simple question like that. Which is exactly why I offered no answer, just the question.
In general, I find questions, and those who advance them, more interesting than answers, and those who advance them, unless the question is black and white, which few interesting questions are.
I am not telling you you're wrong to deal with this kind of question by consulting the BJCP guidelines. But you'll miss many good questions by accepting the quick and obvious answer.
As to this question, Stout v Porter, I have your answer. Thanks.