Some counter points:
1. The number is around 14.5% in direct global emissions [1] according to the FAO, I cannot find any reputable source saying anywhere as low as 2.5%
2. Beef has roughly ten times more carbon footprint as Chicken. Beef has by far the highest CO2 equivalent per KG of product among any food [2] at 99.8Kg CO2 Equivalent, lamb / mutton comes a distant second at around 40Kg and Pork / Poultry are around 12/9 respectively [3] .
3. Looking at American consumption and emissions in isolation is disingenuous, USA alone exported 2.2 Billion pounds and imported 4.4 Billion pounds of beef and cattle in 2020.
4. Beef related food production is the leading cause of deforestation in many countries including Brazil [4] and a lot of it is export driven. There is additional secondary emissions due to this type of deforestation .
5. In addition there is substantial growth in amount of meat consumes as a country develops the impact of this industry is not just current emissions [5]
6. A lot the byproducts that become animal feed can also become fertilizer, if used in feed stock then likely it is organic and therefore contains fertilizer components such as Potassium , Nitrates etc that can be processed as fertilizer .
7. Even if there was zero emissions related to consumption, it is inherently a extremely cruel industry, the conditions in dairy/ cattle/ chicken/pig farms are horrifyingly bad to the animals, and use breeds that have little genetic variety, create potential outbreak zones for many diseases.
8. Pigs and Cattle are very intelligent species, it is especially cruel to breed species of higher intelligence just for food even if there were only humane farms.
[1] http://www.fao.org/3/i3437e/i3437e.pdf
[2] https://science.sciencemag.org/content/360/6392/987
[3] https://ourworldindata.org/environmental-impacts-of-food
[4] https://iopscience.iop.org/article/10.1088/1748-9326/10/12/1...
[5] https://academic.oup.com/jn/article/133/11/3907S/4818041