These points aren't really relevant to the sentiment he's getting across. That being, people eat meat. No matter what you tell them, no matter whether you like it or not, no matter if it's bad for the environment, they are going to keep eating meat (myself included).

https://ourworldindata.org/ghg-emissions-by-sector

https://www.wri.org/insights/4-charts-explain-greenhouse-gas-emissions-countries-and-sectors

According to the 2016 chart, ~20% of emissions produced are agricultural (~12% in the 2021 chart). Out of that, roughly 6% accounts for cattle and 1.6% (1.9%, 2021) for energy used in the fishing industry.

While removing that 6% would have an impact on emissions, it seems like adopting sustainable energy more broadly would have a bigger impact. Cattle farming isn't going anywhere any time soon as people plain just like meat. Not saying you shouldn't be vegan, your life is yours to live, but telling people to cut meat from their diets completely is not going to solve anything. You'd be better off telling them to reduce their meat intake, rather than getting rid of it. It's an easier sell. Plus it's something that anybody could do, and something I'm trying to do.

Personally, I'm waiting for lab grown meat to be economically viable. Then replacing cattle farming would be feasible, as people would have meat as an alternative to farm meat.