The model railroad in question - is a model railroad.
The name of the publication in question - is Model Railroader.
I don't see any adjectives like, "Scratchbuilt, modeler assembled, non-commercial," or similar in the title of the magazine.
Applying the reasoning implied in the original question, maybe MR shouldn't have reported on the layout at the Museum of Science and Industry in Chicago. After all, it was built by professional model builders under contract. Or is there some dividing line between 'acceptable' professional building and 'unacceptable' professional building? If so, where is it? Who drew it? Lacking an answer, I don't see any problem with MR featuring professionally built layouts any more than I have heartburn about them featuring custom built locomotives.
Back when I was routinely working 60 hours a week, I would have loved to hire a professional to build a layout for me - if I also had had the space and the disposable income. If someone DOES have the space and disposable income, more power to him.
Chuck (modeling Central Japan in September, 1964)