I haven't read it all (I should be doing physics revision!) but I read some of the links to get the jist before I replied. I'm vegan, and I don't consider myself a "purist" however I also don't believe that it's in the benifit of veganism principles to just forget about the little ingrediants.
So, this is what I feel and how I think.
I think the little ingrediants can be important, for many reasons. Upholding a consistant image of veganism is important to me, because it enables veganism to become accepted, and vegan products be labled, which help the vegan cause as it makes veganism easier. To acheive this, there must be a definition of vegan (no animal products, not tested on animals, I think is the rule of thumb), and vegans must uphold this definition where it is practicable. Furthermore, little products from animals in big amounts still equal profit for the animal-exploitation industry. Also, everytime you don't buy a product because of a little animal product, and do buy a vegan product, you're affecting the supply-and-demand for vegan products.
I think that there's a difference between getting worked up about ingrediants which are unavoidable, and convincing yourself that ingrediants are too hard to avoid to be worth bothering about. To me, there's a difference between saying "it's not worth worrying about" and saying "I'm doing my best right now, and that's enough".
I appreciate it's easier for a lot of people not to sweat the little ingrediants, which enables them to make a huge difference with less headache and I don't think this is a bad thing, and I don't think they're any less commited because of it. Infact, it allows vegan principles to be acessed by people who'd otherwise be put off by veganisms strictness, and it allows people to see there's more than one way to reach a common aim. As far as I can see, they're commited just as much to the same cause as me, and this is good. Their approach is different, their lives are different, and that's fine. I didn't become vegan overnight and I'm happy that in my inbetween stages I was just as commited as I am now, I was just doing as much as I could.
So, in short: I think the little ingrediants are important, but I applaud anyone trying to reduce their animal consumption and if it's not right for them to sweat about them, as far as I can see their no less commited, they're just not "vegan".