"You don't have to be vegan to think that unnecessary cruelty should be avoided"
I'm a meat-eater, but I'd take issue with this.
If you accept other people eat meat (they do) then there's no unnecessary cruelty involved in fivers. Because no animal was killed for it's tallow. The animals were killed for meat or fabric, the tallow is a by-product.
If the animal has been kiilled, far better to make use of it than waste anything.