I'll put it this way for you. If I weren't an eager young libertarian on winter break, I wouldn't have touched Stefan's book. In fact, if he hadn't personally offered to give it to me, I probably wouldn't have picked it up. If I hadn't made a bet on the content of the book, I wouldn't have likely made it past the first few pages.
The honest truth is that there's a whole lot of philosophy out there that I'd like to read, and I'm not reading it in order to read Stefan's book. I'm enjoying the opportunity to be involved in something new and exciting, and the ability to actually offer feedback to someone I respect. But at the same time, I was probably going to read a little bit of Michael Otsuka's Libertarianism without Inequality and G. A. Moore's Self-Ownership, Freedom, and Equality, and then try to get my hands on a copy of Derek Parfit's Reasons and Persons if I weren't reading Stefan's book. Say what you want about the quality of academic philosophy (I certainly don't agree with Otsuka or Moore), but it's important that I read those books. I'm working on my thesis concerning ethical dilemmas arising from global climate change, and their ideas will play a role in my work. I'm not sure that Stefan's will.
I really don't want to come out sounding like I don't think much of Stefan, because that's totally not the case. He's incredibly intelligent and insightful, which is why I'm reading his book. But my point is, if you knew what you were talking about, then you wouldn't be saying what you're saying. Think what you will about academic philosophy, but what you're saying is essentially the same as saying that you know more about global warming than climate scientists, or that you know more about art than an art critic, or...oh wait, you might think those things.
I guess the only reason I might be coming off as hostile is that you suggested that my standard of "what academic philosophers will accept" is somehow weaker than "what is correct." In reality, non-academic "philosophers" will accept a lot of arguments as being "correct," even though they are fundamentally flawed. Academic philosophers are trained for years to be able to spot flaws in arguments, and to interpret precisely what is said. To think that an academic philosopher will be somehow less able to spot an incorrect argument than anyone else would be preposterous. In fact, my entire point is that it is this ability to detect flawed arguments that will turn many professional philosophers off of Stefan's book prematurely. The thinking is not, "Oh, this guy hasn't studied Berkeley enough to be in our club." It's rather that "If this guy would say something so obviously objectionable as _______, as if it were common sense, he couldn't possibly have enough experience with philosophical ideas and argumentation to produce something worth looking at. I'm going to go read something else instead." And let me be clear about two things: as an academic philosopher, I personally know that I put down works of academic philosophy when I read things that produce that kind of response, and I am finding a bunch of ideas in Stefan's book that would produce that kind of response. I just think that Stefan's errors are arising when he wanders outside of his area of focus, and he would avoid these problems if he stuck to what he's best at, which is ethics and political philosophy.
It's past my bedtime; I hope this hasn't been gibberish! 