It turns out the fact that they were a liberal church, too liberal for him, was the reason he decided to commit murder during a children's program. From the News in Knoxville, TN:
Adkisson targeted the church, [Knoxville Police Department Officer Steve] Still wrote in the document obtained by WBIR-TV, Channel 10, "because of its liberal teachings and his belief that all liberals should be killed because they were ruining the country, and that he felt that the Democrats had tied his country's hands in the war on terror and they had ruined every institution in America with the aid of media outlets."
Adkisson told Still that "he could not get to the leaders of the liberal movement that he would then target those that had voted them in to office."
Adkisson told officers he left [his] house unlocked for them because "he expected to be killed during the assault."
Inside the house, officers found "Liberalism is a Mental Health Disorder" by radio talk show host Michael Savage, "Let Freedom Ring" by talk show host Sean Hannity, and "The O'Reilly Factor," by television talk show host Bill O'Reilly.