Begins to wax sentimental over some variety of meat they could never give up.
The omnivore, even if it’s just subconsciously, is opening themselves up. They’re going to miss a certain bit of flesh that they have some cultural/sentimental/personal attachment to. A good vegangelical will talk to them about the alternatives that modern vegan science has provided, “Have you heard of Morning Star Farms? Check for egg whites though!” The omnivore will often refuse to give up this bit of flesh.
Now the question is, what is best to do in this situation, for the animals?
It seems obvious, give up on conversion to ethical consistency.
Why not just eliminate all the other bits of flesh and secretions and ova from the diet?
Er…A bird in the hand is worth two in the bush, right?