The thing that hurts is that it probably only made you think because in the same way we notice a father, or other relative balding, and we reach a certain age, it dawns on us that this could be a reality. As you say it's not going to work as a retort because 1) people won't have that empathy towards you as a stranger, that you would have with your brother, and more importantly 2) they won't have that empathy because you don't represent the same thing happening in them.
Let's face it, if a lot of us were perfect NW0's and never spotted a single hair on a towel or pillow, we would likely be just as ignorant towards baldness as the people we despise. But then again it's all circumstance, mentally and physically it's what constructs how we are, and we can talk about parallel universes but in this one we at least are not ignorant and completely superficial full heads.
So from this un-desirable disposition, either we can at least take from this that we are more empathetic towards others feelings and more of a thoughtful and mentally evolved human being, or we can despise all forms of deformity just as we despise our own.