Earlier quoted context omitted.
Is it? What empirical evidence do we have that mandatory veganism or outright banning of cars would be a net positive, let alone feasible? To me those two ideas sound like perfect examples of the non-empirical lofty ideals that the previous comment was rejecting in the very first sentence.
Not advocating for it but _eventual_ transition to veganism would definitely be a net positive (lower carbon emissions, land and water use, horrors of factory farming, mental health of the factory workers, exploitation of immigrant labor, etc.). Most of the arguments I've seen from the Veganism movement seem to have sufficient scientific backing.
Veganism to reduce carbon emissions and animal suffering, a car-less society to improve communities and public health, and the right to bear arms for the security of a free state are all lofty ideals. However, we have no examples or reasons to believe that enforcing the first two by decree is even feasible, nor can we imagine the unpredictable side effects. On the other hand, there are many examples of states where gun ownership is heavily regulated, restricted, or virtually banned which however remain secure and free and with no obvious downside.