> I was taught to gut a squirrel by the son of a freed slave

Why gut squirrels

That isn't what was written on the letter, that was the commenter's own writing.

Because if you want to eat an animal you have to properly remove the bits of it that will make you sick and spoil the meat.

We do it to pigs and chickens and cows too. Its a very early step in the slaughtering and butchering process - usually the first step after the animal has been killed.