I don't think "don't follow your passion" is any better advice than "follow your passion". I think better advice is "recognize whether your passion is likely to be a viable career". As Tony Robbins put it, everyone should do something they're passionate about, and maybe for you that will be a hobby.
My daughter deliberately chooses NOT to work doing the things she loves. She reasons that if she is **forced** to do something, day in and day out, for years, she'll get sick of it, that it will become a chore, and will no longer be what she loves. She doesn't want to lose the passion she has for it, so will keep it an avocation, not a vocation.
My issue with "follow your passion" in addition to the cogent points you make in your book is that college students have no way of knowing whether they will enjoy a particular field.
Graphic Design is a horrible choice for most artistically inclined individuals - because the typical graphic design position is all about understanding and interpreting other people's business objectives - something your average artist is not well suited to do.
The skills and personality required to succeed (and be happy) in various jobs are not easily discerned from the outside. Plus a job that is miserable in one company - could be highly rewarding in another simply because the culture is supportive and collaborative in one place, but petty and cut-throat in another.
People say you should turn your hobby into your business. My feeling is the quickest way to ruin a perfectly good hobby is to turn it into a business. Passion is another story. Typically a person who sucks at math will be a whiz at geometry if geometry is a necessary ingredient to accomplish a task that deeply interests that person. That's how I define passion and everyone has it buried in themselves somewhere. The secret sauce is simply a matter of whether or not you can glean opportunities from whatever it is that lights your fire. Some people are better at finding and capitalizing on opportunities than others. Those that have that knack will usually be successful.
We totally haven't seen it on your blog before Scott. There's no way you talked about how your passion usually follows your success and that your success in the long run is determined by setting up the right processes. So there's no possible way you've talked about being really passionate about something is more of a reward for finding eventual success from those earlier processes.