Skippy's right: It's time to fight fire with fire.
Here's what I wrote. I didn't feel the need to summarize the whole brouhaha, and got right to the heart of the matter:
Just a quick note to let you know that I won't be buying any Dunkin Donuts coffee or doughnuts until your company publicly apologizes for knuckling under to ridiculous pressure from Michele Malkin, implying that all Arabs who wear a kaffeyeh (all Arabs, really, is Malkin's point) are terrorists or endorse terrorism. Pulling the Rachel Ray ad due to Malkin's stink was the worst kind of cowardly, and stupid and offensive besides. Malkin exists to drive wedges between people; by playing into her hands, your company has implicitly agreed that Arabs should rightly be suspected of terrorism.
I know in my heart that's not what you meant to do; you simply meant to avoid controversy. But sometimes controversy seeks you out, and a publicity hound like Malkin is always willing to target an innocent company for her own ends. I'm sure you'll get many letters like this one, so at this point, there's no avoiding the controversy. The only question is, which side of it are you on? Do you side with Malkin and her fear-mongering, or are you willing to stand up against the fear and distrust she engenders?
P.S. I haven't seen the powdered vanilla creme-filled doughnuts in my local store for a while. Have they been discontinued? If you do apologize for this misstep, could you bring them back?
If you want to write to Dunkin Donuts, here's their contact form.