I get both sides. Lefty fundamentalists complain about the vigor and robust expansion of Baptist and fundamentalist churches. At the same time some of them ask me to help revive their dying mainstream churches. I can’t help; the Lefty Fundamentalists are the reason their own churches have been dying for four decades.
What happened in the mid 1960’s is that Lefty Fundamentalism, a politically based religion, took over most of the mainstream American churches. The National Council of Churches became a leading anti-Vietnam War organization and took an active role in all Lefty issues of the day. By 1971 the invocations at the start of Congressional sessions, which had always been delivered by a mainstream church minister, were being delivered by Baptists and fundamentalist ministers. The membership of mainstream churches has been in steady decline while Baptist and fundamentalist churches have been steadily growing. We have plenty of old mainstream churches in San Francisco that now house fundamentalist congregations.
People don’t go to church for politics, they go for religion. The Baptists and fundamentalists doesn’t have the same problem. They avoid politics. Only the giant TV congregations are political and their members usually attend local churches that aren’t political. Billy Graham was the penultimate successful Baptist and he stayed far away from politics.
On the other hand, it is hard to think how a religious Christian could be a part of a mainstream church, especially be a member of a Presbyterian church. The Presbyterian church is so anti-Semitic in its international politics that Jesus today would face a Presbyterian church that wants to make sure his carpentry business in Samaria fails and that he and his followers get blown to pieces by Palestinian suicide bombers. Poor Jesus, he might see Mary Magdalen blown to tiny bits at a sidewalk café in Jerusalem, thanks to his disciples church efforts.