Hey, I voted for Alexi Casilla at 2B and Jamey Carroll at SS. Yes, they are not great players, but they are Twins, they are having a losing season and I want them to know that some people like them. The only positions where I did not vote for a Twin have been 1B (Parmelee) and 3B (Valencia).
Fortunately, many voters try to vote for the best player regardless of team loyalty -- otherwise the all-star team would be all Yankees (because they have the most fans). What might be hurting Mauer is what 70charger referred to in his initial post -- the widespread perception that Mauer's contract is one of the worst in baseball. Also, he has been playing a lot more 1B and DH than the other candidates.