A demand for the average American to eat more meat would have to explain, as a baseline, why our already positive trend in meat consumption isn't yielding positive outcomes. There are potential explanations (you could argue increased processing offsets the purported benefits, for example), but those are left unstated by the website.
[1]: https://www.agweb.com/opinion/drivers-u-s-capita-meat-consum...
[2]: https://ers.usda.gov/data-products/chart-gallery/chart-detai...
In reality, I don't think anybody in the US follows the food pyramid religiously. But I do think people (try to) follow the main strokes of what the government tells them is a healthy dietary balance, and so any recommendation to increase their fat/protein intake will result in more meat consumption even if the guidelines doesn't itself proscribe that as the only source.
If you go to Western Europe, they're not drinking lots of skim milk, and if you eat things from the bakeries, there's more butter and not as much low quality vegetable oil or sugar. When my French cousins come here, they find lots of the stuff sold here revoltingly sweet.