Yes this is true but a lot of places can't mantain a sheep herd, because it is too cold or to dry for grasses and food for the sheep

My fiance has a skin allergy to wool

True...and you don't need to live in a house, or use the Internet, or have a bank account, or have a computer/mobile...all things that have caused catastrophic damage to the environment and killed countless animals.

One has to draw a line somewhere- perhaps you shouldn't be holier than though just because you draw the line at "I don't want to see the evidence of the death"

Maybe YOU don't have to eat animals to survive. What a privilege u you have that you live in a place where vegetation can be grown in your area or more likely shipped there cheaply(not free of harm to the environment or people\animals). But your experience is not universal there are places on earth that people live where that is not an option. And some of those people have been living there sustainably for 10s of thousands of years. Not to speak of people who's body needs meat to live because of some other reason. You can not eat animals and that's fine but it doesn't replace the science of how to stop environmental damage.

It's more sustainable to eat the animals you make clothes from.

No evangelizing

I do.

Vegans in western cultures have access to dietary supplements derived from non-animal sources. That's basically impossible without access to modern industrial food processes.

If we're talking about cultures without ready access to plant fibers for clothes, then they're not going to have vegan supplements, either.