I think it has more to do with conservatives constantly calling into RW radio shows and talking about taking up arms against what they claim is a tyrannical gov't. Considering that conservatives have a tendency of showing up at demonstrations while armed, it seems prudent to take precautionary measures, including engaging in heightened surveillance of certain groups that keep on engaging in angry revolutionary rhetoric
"Surveillance of certain groups" is not the function of the IRS. The conversations of random callers on the talk radio is not a justification for the IRS to persecute any group whatsoever, just as the antics of William Ayers are not a justification to persecute ThinkProgress or HuffingtonPost.
You're another goose stepping Nazi just like TM.