From the article
The manager further testified that the Tea Party groups were deliberately grouped together so that they would receive consistent treatment. “There was a lot of concerns about making sure that any cases that had, you know, similar-type activities or items included, that they would be worked by the same agent or same group,” the manager testified.
The two houses of Congress are the people's representatives. They are supposed to be accountable to the people and part of that accountability is taking reasonable actions to insure that government isn't treading too heavily on the toes of law abiding citizens. In light of the current situation I welcome these investigations. At least they're investigating something that matters instead of steroids in baseball.