According to an Interview with craveonline (reliable?), Quinn has lost his way.
The simple fact is that, when a person is raised eating meat, it can produce an addiction that is very difficult to kick, even if the person knows that it's crucial that they kick it (when seasoned & cooked properly, thanks primarily to the fat and salt in the meat, enough dopamine can be produced to create a legitimate addiction).

I'm certain that Quinn knows, in his heart, what is truly right and he will eventually be able to completely overcome this addiction, especially if he makes use of the amazing meat & dairy substitutes that are now available.

www.craveonline.com/music/interviews/144304-quinn-allman-of-the-used
www.webcitation.org/69JvGGtw4
web.archive.org/web/www.craveonline.com/music/interviews/144304-quinn-allman-of-the-used

yay! Quinn is such a rad guitarist.