Dausuul: We seem to be approaching this discussion from entirely different sides here. Let me explain, before you use words such as 'fallacy' when they are not applicable.
I think you misunderstood my statement above. I was not talking about instant agreement with a differring political or (whatever) messages. As much as everyone is free to have his or her own opinion and to make that opinion public, this freedom at the same time exposes the person speaking out to criticism - and rightly so. Discurse - be it political or otherwise - is the thing that keeps any society going. There just is no such thing as "an inherently right opinion" - just an opinion that has stood the test of time, can be substantiated by facts and has weathered criticism levelled at it. Thus, if someone voices an opinion I don't share, I will either listen to it but keep silent (because, let's be honest - not every situation calls for an all-out discussion) or I will try to challenge that opinion. The end result being that no matter the outcome of this discussion, I will have learned something about another person's views on a certain subject matter. This can only serve to further my understanding of said matter, even if I think that the point my counterpart is making is not valid. Again, I am excempting extremist opinions here (see above).
I, in turn, could not disagree more with your statement that 'politics is inflammatory' and 'political views can be a direct attack on people you care about'. Politics, per se, is not inflammatory; it is how certain people conduct politics that makes it (and them) controversial. I have never understood the need for that - a rational discussion is superior in all accounts, even and especially if the subject matter is something I care about. Furthermore, I have yet to encounter any political view that I would consider 'a direct attack' on anyone (the only example I can think of is extremist genocidal politics or something similar). Differring standpoints is one thing, but even talking about 'attacks' in this context is overstating it.
With regard to a certain author: I think we are talking about the same person. And, again, I feel that you are losing out by not subjecting your own viewpoint to criticism, even if it is just derived from differring opinions expressed in a book. You are, of course, free to dislike the writing

- everyone has a different stylistic taste.
Finally, I don't think that your premise is valid where you stated that 'anything you buy is going in part to fund those promotions'. In fact, I would estimate that less than 10 % of the people who share any given view would also supply an organization promoting said views with funding. Just to give an (hopefully non-inflammatory) example: I think that the vast majority of people in any Western country would agree with the goals of UNICEF. However, by far not all of these people also contribute financially.
Long story short - boycotting stores because of things like differring opinion is - to me - overreacting. I go to a store because of product availability, pricing and customer service. I couldn't care less about what the store owner does in his free time.