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...
I really like this study of a population of highly trained athletes and their diets/protein intake: https://pubmed.ncbi.nlm.nih.gov/27710150/
In that study they eat > 1.2g protein/kg body weight, but 43% of that is "plant sources", meaning grains, legumes, fruits and vegetables. Like one serving of oatmeal is 6g, things you don't think of as "protein" add up and you have to count them. The athletes in that study are Dutch and 19% of their protein intake came from bread.
But what always happens with protein recommendations is that they say "x grams protein/kg bodyweight" but people hear "protein is meat, you are telling me to eat x grams/kg bodyweight of meat." Very few people ever look closely enough at their diet to develop an intuitive sense for counting macros.
Your diet contains many sources of protein lower quality than beans (as in the linked study with high level Dutch athletes getting 19% of their protein from bread), you do need to count those. They do add up and if you don't, you end up assuming you need way more protein than you do.
if I'm eating bread, pasta and other cereals, I may exceed the 1.2g/kg recommendations but the PDCAAS (Protein Digestibility-Corrected Amino Acid Score) of these would make it in truth closer to 0.6g/kg.
Someone else eating mostly meat would get in total 1.2g/kg protein but also 1.2g/kg when PDCAAS is accounted for.
Maybe it's to simplify the calculation to the average user but it feels misleading, you can't know for sure the proportion of cereals in somebody diet.