Like most things, they start with a grain of truth and the add some scare tactics.
I grew up in the agricultural and livestock industry. Sure some places and some people use bad practices but, that can be said of any industry or occupation.
As for people making bad choices, you can't legislate health or, tax people into living the way you want them too.
Obesity starts at the grocery cart and ends at the fork. Rarely is meat the only thing causing obesity. The same can said of heart disease and diabetes, though some people do have a genetic predisposition.
In my personal life, I was told salt, eggs and, butter was the enemy and the reason why I had high blood pressure in addition to being a stressed out 'kid'. Of course, this totally ignored my personal genetics. I didn't live the perfect life but, I also spent ~16 hours a day during the summer though Junior and High school farming ~1600 acres and spent the winter chopping ice so cattle could get a drink and feeding range cubes and hay so they prospered in harsh winter weather.
Too much salt is still bad, no eggs (none, zero, zip) for ~3 years made no difference, the savior margarine has ... on no ... transfats and, surprise neither of these made a difference in my personal health.
I totally get that I don't need 5K~8K calories a day of food to do hard manual labor like my ancestors to plant and harvest crops and, that it all needs to be fried for higher caloric intake due to lower crop yields so there is enough left for everyone else to get to have something to eat too.
Today, I don't saddle up my horse or hitch the mule team to the wagon. Driving around for 15 minutes in the Wal-mart parking lot to get a parking spot closer to the door and electric cart might have a little bit to do with things as well. Why walk to the mailbox when I can take my electric scooter, golf cart or, side-by-side?
These arguments all sound a bit like trying to solve air pollution by taxing gas powered weed trimmers.
Taxing and banning things has worked so well in other areas, why it will work in this regard is puzzling at best.
If the government beaurocrats and general do-gooders try to get people to quit eating animal proteins and start eating bugs, that is going to be a hard sell in most parts of the world. For many people, it would be similar to convincing a devote Muslim they should start eating pork because it is 'better for the environment.
I have been fortunate to travel a lot of the world and I have tried food that would be off-putting, or downright nasty, to many people that I thoroughly enjoyed. However, forcing people to do so through taxation or government decree by some foreign beaurocrat is going to get some pretty heavy pushback from people like myself.