Your mistake is here: "The trouble is that “spiritual but not religious” offers no positive exposition or understanding or explanation of a body of belief or set of principles of any kind."
And then you go on to say that we, the spiritual but not religious folks, are in pursuit of happiness without direction. You say that we don't read a cross-section of the right books, and that we can't make a decision. You point out that we don't read the Bible.
You're right that it's a movement against the old-faashioned church institution, but it's also a movement against being boxed in and not being allowed to read other texts. Why should I listen to only one person, and one set of beliefs?
Though you may know me very well, and you might be my best of friends, I'll bet you don't know that I read scripture every day. Sometimes several times a day. I listen to Buddhist lectures. I read Sufist poetry. The other texts you mention? I am not afraid to read! Don't expect me to shout that to anyone else. It's my business.
Furthermore, I don't believe my quiet practice gives me a more personal connection to my Source. To God. Sorry Author, you missed this mark too. It's an intimate connection that makes me feel free and able to play with knowledge.
Your article will create a divide among anyone who reads it. Try messages of unity to make your point instead.