Need to make these people visit a slaughterhouse.
"Our Daily Bread" is a very interesting documentary on modern industrial agriculture, just shows what happens, no commentaries whatsoever.
The last part shows the slaughterhouse process (at least live cow to half beef carcass anyway), fair warning you can't unsee that but imo more people could benefit from knowing how their burgers are made.
From the "Dirty Jobs" TV serie: "Custom Meat Processor" https://www.imdb.com/title/tt1788060/ that includes some self censorship to be able to show it in TV.
Disclaimer: I'm not a vegetarian, but I dislike wasting meat. Something like "eat what you kill" but with in the supermarket in the middle.
Me, having recently moved to rural Ireland: “the cows were mooing and wailing horribly last night, were they being slaughtered?”
Farmer Neighbor (not the one with the cows): “oh, no that’s just when they take the calves away for veal”
As a parent I feel worse about dairy than beef…