The president of another group, the National Organization for Marriage, said the IRS publicly disclosed confidential information about donors. George Eastman said he thought the IRS's release of that information was designed to intimidate contributors to the group -- which opposes same-sex marriage -- "to chill them from donating again."
At Tuesday's Ways and Means hearing, committee Chairman Dave Camp, R-Mich., said the conservative groups were being singled out for their beliefs.
"They are Americans who did what we ask people to do every day -- add their voice to the dialogue that defines our country," Camp said. "And for pursuing that passion, for simply exercising their First Amendment rights -- the freedoms of association, expression and religion -- the IRS singled them out."
The committee's top Democrat, Rep. Sander Levin, said it was time to correct the IRS's problems.
"You are owed an apology," Levin, from Michigan, told the witnesses. "We say to you that each of us is committed to doing our part to ensure that."
But even as they joined in expressing criticism of the IRS's behavior and sympathy for how witnesses' groups were treated, some Democrats tempered that. They noted that the IRS is responsible for seeing if organizations qualify for tax-exempt status -- which includes not approving requests by groups that primarily engage in election campaigns.
"None of you were kept from organizing, or were silenced," said Rep. Jim McDermott, D-Wash. "We're talking about whether or not American taxpayers will subsidize your work. We're talking about a tax break."
Rep. John Lewis, D-Ga., noted that IRS commissioners over the past decade were appointed by President George W. Bush, a Republican, and said, "This has nothing do with red versus blue."
At one point, Rep. Earl Blumenauer, D-Ore., said many of the conservative groups have taken positions on highly-charged political issues like President Barack Obama's health care overhaul and said, "Let's stop this charade of pretending to be just social welfare organizations. Admit they are political and treat them as such."
That prompted an angry response from Eastman, who said that to say "defending traditional marriage doesn't qualify for defense of the public good is beyond preposterous."
Earlier, the leader of a small South Carolina tea party group said her organization first applied for tax-exempt status in 2010 -- and is still waiting for the application to be processed.
"Nearly three years in waiting for an answer is totally unacceptable," said Dianne Belsom, president of the Laurens County Tea Party. "The IRS needs to be fully investigated and held accountable for its incompetence harassment and targeting of conservative groups."
Belsom said her group in rural South Carolina has about 60 members and "seeks to educate ourselves and fellow citizens on various issues pertinent to living in a free country." The group also holds candidate forums in election years, she said.
"I'd like to note that our group is a small-time operation with very little money and this represents a complete waste of time by the IRS in terms of any money they would collect if we were not tax-exempt," Belsom said.