Is it 100% optional? Are there no dietary conditions that require eating meat? Even if it is optional, I only said that expecting everyone to change is unrealistic, not that it’s impossible.

What point are you trying to make here? It's ok for people to support the meat industry because an incredibly small fraction of people need meat? How many people do you know that eat meat? And how many do you know actually need meat for medical reasons? And how many of those specifically require eating red meat, by far the worst offender, the most expensive, and still massively consumed?

How much do you expect people to sacrifice? If you give up eating meat can you fly to go on vacation? Or are people expected to give up everything in the name of the climate while billionaires jet around and corporations expell endless emissions?

"Guys, you don't get it! Doing 100% is hard, so why can't people just do 0%?!?" Also, you can criticize people for eating meat and still criticize billionaires on private jets; but nice whataboutism, I guess.

If military operations are required for survival (like eating)

You don't need to eat meat.

“yes we will only defend that military base and we will not kill everyone in the nearby school” and then they go and kill everyone in the school, why wouldn’t they be blamed for not following their orders?

Pray tell, what is the meat industry equivalent of this? You can't not worsen climate change with a meat industry. And before you argue "lab-meat", 1) that also takes a lot of resources currently, and it hasn't been massively adopted so ti's not what people are eating, 2) you know whether you're eating lab-meat. You can't support the meat industry, which you know is responsible for climate change, and then pretend you don't know the consequences. Stop.

But fine, you want another example, think of a hitman. "They only hired the hitman to kill people, they are not morally responsible for the hitman killing people". Except in this case, the hitman is also raising his victims from the ground up and worsening climate change.

You know eating meat, and thereby funding the meat industry, is bad; stop wasting time trying to justify it to yourself and other people and engaging in some kind of double think, and start actually making change for the best.