they used it for a reason and that's how they lived back then.
I understand your point, you see it as a cruelty towards animal. back in those days they only used dead animals skin, when they die not killed.
whereas its little bit different these days where we create demand for leather products, most of us want leather sofa, leather interior in the car, leather shoes , belt, ladies bags, feather jackets and many more I can count... and big companies fullfil our demand providing us with leather and feather products and in this case animal don't die naturally, they get killed and this is disturbing bro.
and we still like to regard ourselves as vegetarian.