No one can claim with any authenticity that they are 100% self-taught. I've learned lots about photography by reading books, but I don't consider myself self-taught. Just because I took the initiative to read books on the subject and then apply that knowledge, doesn't mean I'm self-taught. I learned from the people who wrote the books. If you've ever learned something here on APUG, then you're not self-taught, you learned from the helpful people here.
I think most people use the term "self-taught" to mean "no formal education" and that learning something without a formal education is a badge of honor. Whether you learn from attending a class or from a book, or a combination, what does it matter? Learning takes work no matter how you do it.