The emissions alone are enough to make us miss climate targets

To have any hope of meeting the central goal of the Paris Agreement, which is to limit global warming to 2°C or less, our carbon emissions must be reduced considerably, including those coming from agriculture. Clark et al. show that even if fossil fuel emissions were eliminated immediately, emissions from the global food system alone would make it impossible to limit warming to 1.5°C and difficult even to realize the 2°C target. Thus, major changes in how food is produced are needed if we want to meet the goals of the Paris Agreement.

(emphasis mine)

https://www.science.org/doi/10.1126/science.aba7357

The level of harm is an order of magnitude different. It's not quibbling over some small details

To produce 1 kg of protein from kidney beans required approximately eighteen times less land, ten times less water, nine times less fuel, twelve times less fertilizer and ten times less pesticide in comparison to producing 1 kg of protein from beef

https://pubmed.ncbi.nlm.nih.gov/25374332/

Moreover, mandating a consumption level like that is exactly how one keeps factory farming just as entrenched as it is today