Any attack on the credibility of the IRS matters because soon enough, it will be forcing us to buy things, as well as regulating speech. Obamacare's unprecedented expansion tasks the IRS as dispenser of the "penalty" coercing Americans to partake in a collective health insurance scheme -- and discerning the intent of more than 40 new taxes, to boot. This will be handled by the same fine organization that was recently hit with a class action suit alleging it improperly accessed and stole the health records of some 10 million Americans -- some 60 million medical records, including psychological counseling, gynecological counseling, sexual/drug treatment and other medical treatment data.
Yes, reasonable people understand that government isn't systematically trying to find out what they had for breakfast or what they watch on TV. That would be as paranoid as believing that the National Rifle Association and the Koch brothers have the power to control millions of voters. But rational people understand that abuse happens. If you're worried about the government's invading your privacy, there is no agency with more means to do it than the IRS.
So though this is a fine time to push the politics of scandal -- because occasionally, politics is substantive -- it would be more constructive for the GOP to push for tax and IRS reform.