I think that this is just silly.
I can understand the idea behind it, that those who are using tax breaks and loopholes to avoid paying taxes when they should, should not have a say in how the laws and government is run. Doing this, however, hurts MANY other people that work just as hard as anyone else.
People that work for charities, churches, and other things that are tax-free would be hurt by this. Students and unemployed people will be hurt by this. Very low income earners will be hurt by this.
The idea that every citizen in the country over the age of 18 has a vote is part of what makes the United States the land of opportunity. When you start restricting rights like that, it becomes the land lead by the privileged few (even moreso than it already is...but that's another rant entirely :) )