From your source:

"Amid growing evidence that public television stations in several cities have shared their donor lists with both political parties."

and

"Yesterday, Cecily Van Praagh, a spokeswoman for WETA-TV in Washington, acknowledged that the station also traded donor lists with the DNC and other political organizations, "both conservative and liberal.""

and

"At a third television station, WNET in New York, dismayed executives said they discovered yesterday that a "list broker" working for the station had shared the names of donors with the Democratic and Republican parties...."

and

"At the Republican National Committee yesterday, spokesman Michael Collins said, "To the best of our knowledge, we have never leased any public TV station donor list." He said he could not rule out the possibility that the RNC leased a tax-deductible organization's list, but said the party always used "a list broker and paid market price for the lists."...."

Why should they not sell or trade their mailing lists with whoever will pay and/or reciprocate?