My brother, who is a missionary btw, repeatedly yammers on about how evangelicals arepersecuted by government.
Ergo: I think their thinking about the matter goes something like this.
1) Christians are persecuted/discriminated against by government.
2) America was founded on biblical principles and men of God.
3) that first amendment stuff isn't what they really meant- that's just the view of those who are persecuting us.
A 'logic'- if you can call it that- that is circular and self-sustaining.
Be the love you seek.