I imagine that's like the many Christians who say they are Christians and believe in Jesus Christ but never go to a church (or only go at Easter).
So I suppose it's actually two different questions. One is what main religious path in life they feel they are on. The other would be how strictly (I was going to say "religiously"
) they follow that path - if they do actually do the actions normally required by their path, or if they are more laid back about it.