Maybe the reason Life said what they said, was knowing if you travel this section of the Lincoln Highway you will cross large desolate areas as you traverse the route, with few or no signs of civilization. They seemed to be almost laughing at the desolation of the state compared to states on the East Coast and particularly New York City where Life was based; at the time having a larger population than the whole of Nevada with a little over one million residents and Nevada being nearly 400% larger in size.
…but Nevada officials took the slur as a compliment and started an advertising program using ‘Americas Loneliest Road’ as an advertising slogan to get tourists to an area they might not ordinarily travel across.