Religious “Indoctrination”?

I am really confused by Charles Blow’s confusion in the opening paragraph of his latest column:

…most children raised unaffiliated with a religion later chose to join one. Indoctrination be damned. By contrast, only 14 percent of those raised Catholic and 13 percent of those raised Protestant later became unaffiliated.

So kids raised unaffiliated feel free and even inclined to join a religion if they want to. Those raised religious don’t show similar independence of mind.

And this is supposed to prove that religions don’t engage in (effective) indoctrination?

If he’s trying to prove that religions are good because lots of unaffiliated people like to join them, he really should consider the number-one finding from the Pew survey he’s citing:

The category of people who are unaffiliated with any particular religion has grown more rapidly than any other religious group in recent decades. According to the 2007 Landscape Survey, 16% of American adults say they are currently unaffiliated with any particular religion, compared with only 7% who were raised unaffiliated.

By Blow’s (unstated) reasoning, being unaffiliated is good because lots of people are becoming unaffiliated.

I don’t think that’s what he was trying to say. But in any case, I would suggest the causation is opposite.