In order for this guys argument to hold water he should have used a case other than height which involved a component of personal choice and invoked the same feeling of injustice in people.
Hmm. No one chooses their parents. Should rich kids be taxed like poor kids?
> Would you agree that taxes should be just?
I'll agree that "just" has no agreed-on definition and is used as a way to imply that the other person is bad. As such, I find it a useful signalling device in a discussion.
Are you certain that you don't want to argue that "just", the word on which your argument and position depends, actually has a useful and good meaning?
Because of that I think that the comparison of using height as a deciding factor in taxation is like comparing apples and oranges.