Yep. Even a 2000 calorie diet of all fruit and veg (no fatty fruits) will end up with around 10g fat. That doesnt mean that 10g fat is optimal but it is virtually impossible to be deficient in EFA's.
So just like one could say that there is no essential carb, another could say that there is no reason to eat fat. But neither way is optimal for health.
Who said anything about b12. We're talking about FAT. Essential fatty acid requirements can be met by fruits and green vegetables alone. Neither carbohydrate or overt fat sources are essential. It doesn't make them optimal or desirable but you hear the "no carbohydrate is essential" catchphrase all the time from committed low carbers.
B12 is irrelevant to that example. He's making the point that the human body's requirement for dietary fatty acids is theoretically very low, as with carbohydrates, so it isn't logical to claim the body needs fat but not carbohydrates. Same for other things as well, like cholesterol and sodium. But does anyone on this forum recommend only eating the bare minimum requirement for cholesterol, sodium and fatty acids?
But glucose... who needs it, right?
All you can do is what works for you.
If its not working tweak things around and find what fits you best.
It's a straw man argument anyway, since people who favor low carbs are not saying 0 carbs, although those who favor extremely high carb extremely low fat diets are claiming that they are.
Claiming the fat in "green vegetables" is enough really is saying that <2 grams of fat is enough. Backtrack and claim you meant "avocados" if it makes you guys feel better, but avocados aren't a green vegetable any more than tofu is.
How is it not equally ridiculous to argue that carbs aren't essential because we can produce glucose via gluconeogenesis? I think the de facto argument is including all macros is more likely to be optimal; relying on secondary processes for fats or glucose isn't necessarily optimal for most even if it's technically possible and livable or, at times, an extremely beneficial hack that modern humans discovered and ancient humans resorted to for survival, not for everyday idealistic living.