A blog post from the Washington Post suggests that the primary groups 501(c)(4) is intended for are volunteer fire departments and civic leagues; I concede that those groups do indeed contribute to social welfare. I don't see the San Fernando Valley Patriots (see below) under that rubric; but the definition of what is allowed is frankly fuzzy (another reason to get rid of this). To see just how fuzzy, read the official IRS definition:
Types of Organizations Exempt under Section 501(c)(4)
Pay particular attention to the link Organizations that engage in substantial lobbying activities, to see how fuzzy.
But section 501(c)(4) does exist, and these groups tried to get the status, and the IRS had the nerve - the gall - to ask them questions about how they operate! I can still hear the sweet, can-you-believe-this tones of Ms. Karen Kenny, of the San Fernando Valley Patriots, complaining that they had asked her organization (I summarize, but read the KQED text) if it had ever broken the law during protests, and whether they ever planned actions that would break the law. "We're the San Fernando Valley Patriots," she said offendedly, "not Occupy Oakland."
I have news for you, lady. Part of the IRS' job is to find out if applicants for a 501(c)(4) exemption are doing more political organizing than the law allows (however much that is). This may come as a surprise, but the San Fernando Valley Patriots are not above the law. Neither are organizations that have the words "Tea Party" in their name. If you want this tax exemption you still have to comply with the existing laws and rules, and the IRS is entirely within its mission to ask you this stuff.
I still think that 501(c)(4) "social welfare" organizations are political organizers in sheep's clothing, and they should be treated like political organizations and forced to disclose their donors. But as the law stands, they're entitled to tax exemption if political activity is not their primary focus. And that means that when the IRS asks them what they do and how they do it, it is merely doing the job we pay it to do.