I certainly love looking at gun photos and I do not care what is in the photo other than a gun(s). However, I am into guns and not knives...
Exactly, as far as I am concerned, anyway.
My take is that this is a matter of one or two things. First, the article(s) you see may be part of the "daily life" of the owner and it may be satisfying to him to see the assemblage, rather than just the gun by himself. I have no problem with that.
Beyond that, inclusion of anything in the picture other than the gun itself moves the photograph into a different category. A photo of only a gun is a record shot, basically, no matter how artistic the setting. It's an image of a specimen. When things are added to the photo, the attempt is made to move beyond that. Whether or not the photographer is successful is up for... debate.
I once sat through an absolutely spell-binding presentation by a man named Gerhard Backker at the Winona School of Professional Photography. He was a fine arts sort of guy and dealt more with elements of composition than he did techniques of photography. His presentation's purpose was showing us the effect on the viewer one could achieve by skillfully adding and removing "props" from photos, and then explaining why this was or was not effective. Since this all dealt with fairly mundane things (usually food, clothing, and other various stills like you might see in advertising photos of the period), you would think a lecture like this would have been exceedingly dull. It was not. Gerhard is gone now. If have misspelled his name, it's an indication of my middle-aged senility, not a lack of esteem.
One of the great things about this forum is the photography. There are some really nice photos here and some very skilled photographers. Like Oldman45, I love to see the guns, but I enjoy the art, too - when it shows up.