Those are fair points, but I’m not convinced that fur doesn’t have an impact.

Anecdotally, I have a mild cat allergy and own a cat. Vacuuming our sofa regularly makes a huge difference, as it gets rid of the fur stuck to it. It goes from feeling scratchy to totally fine.

Maybe clumps of fur are common with super fluffy pets? Ours is a shorthair and shedding leaves single hairs lying around.

Matter is conserved, sure, but fur with dander stuck to it from saliva versus skin with saliva on it, surely makes a difference?