It must be part of their talking points memos. It's used enough (without one attempt at verification). In a dictionary of denominations I was reading the other day, they listed a whopping 120 or so. And how different is the AOG from Foursquare from Pentecostal Church of God from Church of God - Cleveland, TN? Not very. More bureaucratic differences and differences in church government than actual doctrinal differences. Similarly with the multitudes of Baptist denominations. But it sounds cooler to say 28,000.
Is it? I admit I don't know how the number is chosen, but think about it for a moment. With what I have seen here it is entirely conceivable that each "independent non-denominational" Christian church is teaching its own particular version of Christianity. There are enough variables for this to be so. Imagine you move to a new town and are looking for a good "Bible-based" church. So you start going to Pastor Bob's. This seems good until one Sunday he starts talking about free will.
Well, that's out, so we go to Pastor Rick's. Things are good for a months and then, out of the blue Pastor Rick starts totally screwing up his sermon on Revelation. Darn, gotta find a new church.
Then you go to Pastor Bill's. He seems reasonable, then one day he starts talking about when Jesus became God. He thinks Jesus became God at His Baptism. Well that's just wrong.
Pastor Mike's church is very friendly and we asked a lot of questions before we decided to join. And then last week he revealed that the Holy Spirit told him that Jesus was a second God.
Do you see the pattern? Without a written Catechism and strongly influenced by the pastor's own personal interpretation it is entirely conceivable that no two "independent" churches teach the same thing. And the people in the pews are only there as long as the pastor agrees with them.
SD