Good point. Though it may be best to assume that "the law" is not about equality, justice, or uniformity; but it is rather about arbitrarily enforced rules that are themselves arbitrary, this allows the state the maximum power with the minimal justification. (I posit that this model is already in effect: consider both murdergate and the Obama eligibility cases.)
Given the above, it does bring to mind the question of "pedophilia." For maximum state-power, and "uniformity of the law", they could declare that the same definition of "child" applies as that for parent's insurance: 26 years old. Then, applying this definition retrospectively -- it can't be retroactive, that'd be too close to ex post facto -- we get lots of people who must now be registered sex offenders (everyone who's married, or had sexual intercourse with, someone under 27)! That in turn requires them to be registered and allows them to be disarmed as they are obviously prohibited persons.
That is, I think, the way that things'll end up: where everything that could be considered a 'right' is instead contingent upon government approval... and government approval can be withdrawn at any time, for any reason, to include past formerly-approved actions.