Is Darrell Issa Out of His Depth?

The reason I ask this is because Rep. Issa's investigation into the overreach by the IRS into the business of various educational and social groups has hit a certain self-created snag:

Issa seems to think investigating any groups at all is a definite problem on one hand. 

But it seems like he doesn't care that progressive groups were targeted more frequently than conservative groups.  He might be able to enlist sympathetic Dems to look into the matter if he acted as though the investigation of liberal groups was a problem just as the investigation of conservative groups was a problem, but this just doesn't seem to be the case in his mind. He is okay with liberal groups being investigated. Memory of ACORN and all that.

But heaven help you if you touch the chinny-chin-chin of a billionaires' boys' club like Crossroads.

Is there some reason he isn't supposed to be treated with skepticism by Democrats who naturally think he might be being a bit partisan, here? I'm finding the logic hard.