Mark,
Both your and my view are right, just let me explain why:
The point where to draw the line between depiction of light as primary subject and the use of light to illustrate properties of another subject is individual. Both your and my view are valid, none is universally valid.
Just a little food for thought:
Any photo consists of captured light.
The light originates from one or more sources, is reflected or retransmitted by fluorescence and re-radiated to be captured by the lens and transmitted to the film/sensor creating a (latent) image.
This image is displayed either by printing it or be electronic means (screen).
The pattern recognition in the brain paired with the individual experience reconstitutes the image and divides it up into different structures - objects, beings, attaches names to it and establishes relationships (in)between the seen and yourself.
What is the subject, what is background, what are the different meanings?
All this happens in each viewer's brain.
Any judgment of what is what and the order of importance depends on the individual context - cultural, education, personal experience.
This was more the one step backward to get a larger view of it. I know this is nothing new for many readers (Including you I think, so please don't take offense) , but I think it is worth mentioning it at least from time to time.
I clearly enjoy the different views - especially when these are combined with the understanding of the difference and without anybody claiming the the only valid view for himself.
Best regards,
Michael