I hear you, and I can understand your frustration. I think your formerly focused conversation about taxes and "middle class interests" is now a scattershot of other issues.
There are likely many middle class voters who are voting their pocketbook. They may reject the Glenn Beck aspect of the party, like you may reject some aspects of Obama or the D party. Your disagreements aren't enough to dissuade you from voting Democrat. Currently, right or wrong, these middle class Republican supporters believe the general financial underpinning of the Republican party is in their best interests: strong defense and less of their money taken by the government.
To get them, the Ds would have to prove their beliefs are incorrect and provide an answer to their concerns.
I will add that the debacle of Iraq and Afghanistan has made some of these people a little weak in their support of what constitutes a "strong military."