No. The writer of the song provided the context.So 1 person (you) says he knows the "real" context while the rest of the globe sings a song that makes no biblical point, but they feel good so kudos for that.
Jon, you are digging deep to try find something edible from a song that is void of any substance.
I shared the words. No one is going to make the connection you are trying to make.
Likewise, Debussy provided the context for Par les rues et par les chemins. I've seen Ibéria (the second piece of Images pour Orchestre) performed a few times, listened to it a hundred times and Par les rues et par les chemins is a favorite.
BUT without knowing the context I doubt I would enjoy it so much as the imagry (the actual subject matter) would be missing. It would still be a great composition, but it would lack what is being communicated.
Many songs are like that. Daniel (sung by Elton John) only communicates the meaning of the lyrics when you know Taupin wrote the song after considering the men returning to a small town after the Vietnam War (writtten from a younger brother's perspective). While the song is still abstract, without the context it's just a pretty song that does mean much.
And Elliot's hollow men were not really stuffed with straw. Brownings Childe Roland to the Dark Tower Came was illusionary (you can't pin point a subject matter) yet it still communicates very well.
But once one realizes Miles wrote the song about the John 20 account of Mary's encounter with Jesus then the context supports the subject (worship).
The problem is today worship often takes a back seat to a sermon. Both are equally important. But some cannot tolerate the biblical narrative as a whole because it is emotional. Others cannot tolerate the biblical narrative because it is objective truth. Both of these types of people are the worst for their predjudices.
Literacy has been lost in our culture. For some reason we have largely become a society that is limited in comprehension. We read as if we were reading newspapers. It is sad. But you have to remember that we once valued depth.
Anyway, to answer your allegation, it is no secret that In the Garden is about John 20. The writer provided the context for the song (Miles wrote the song in 1912 and provided the context). That you were unaware has no relevance.