I think the most useful statement in the article is "the sidewalls don’t really hold up the weight of bike and rider. It’s the air that supports the weight." And note that this statement is true no matter which part of the tire is contacting the road at the moment. So his third conclusion "Using the tire sidewalls to hold up the rider results in a regressive spring rate. This can result in the tire collapsing suddenly." is contradicted by the earlier statement. I would say instead that a tire deforms quickly under a certain air pressure given the weight being supported. The reason the sidewall deforms is because the tread can't - it is plastered against the road surface! Our eighth grade science teacher taught us about Boyle's law using bicycle tires. He had us note how an automobile could be held up by as little as 10 lbs of pressure but a bicycle tire could be squeezed by hand (back when most of us had balloon tires - it is even more pronounced with low volume 23mm tires).
The combination of tire pressure, tire type (tubular/clincher/tubeless), rim width, rim volume, rider weight, riding style and a few other things I'm probably forgetting means that making a binary statement like "a wider rim is better/worse" is rather foolhardy.