The central point being that, yes, Beck was trying to find common ground for a gathering of people who respect life and the rationale that there is a Power Greater than us.
His leftist-bashing sort of takes away from that argument (not that I disagree with it), but the central point is viable and accurate.
Any approach other than this would not have worked so well. The religious right is rather dogmatic about religion, especially Christianity and Beck, I'm sure, felt that it would be folly to cater exclusively to that club but to invite other points of view, other religions, other philosophies to the rally. I'm not sure that the religious right found that oppressive or argumentative - perhaps nothing more than inclusive.
When you think about it, this is the kind of approach that worked for Obama so well. This is not to suggest that everybody at that rally had the Obama-like worshipful glow, but that Obama's handlers did find the chord that he could strike. Events such as this are reflective of that approach, methinks.