Why Obey the Law?

A commentor on one of my recent postings asked why, if he, the writer, felt that a particular aspect of the Law (in this case, a law requiring the use of a bike helmet) was unfair, and he opted to disobey it, that meant that, in essence, he granted liberty to others to disobey parts of the law they disagreed with.

It is a fair question - and one that requires a thoughtful answer. So - here goes:

This is not a matter, really, of legal interpretation, or of choice, but one of ethics, and theology.
I assume we are created, essentially, equal. Therefore, we share the same natural freedoms (rights, if you will), the same natural needs, and the same natural responsibilities towards others. As children, we are concerned, vitally so, until we are taught by experience that it just is not so, that we (and others) are treated fairly. "No fair!" is a common, and accurate, playground cry.
Well, the Law, as it stands purports, at least, to deal with all people fairly - hence the blind-fold on statues of Justice. That it does not succeed in this, I grant, but that is largely because we are, ourselves, fallible, weak, imperfect people, and we do make mistakes.
However, in theory, at least, the Law treats us equally. Any law, then, that treats us unequally - and it matters not, for this purpose which of us gets the short end of the stick, is inherently unfair. If, then, motorists are required, for their own protection, to drive in certain ways, to use certain equipment (like seat-belts), and generally to treat other road users as they would be treated, then does it not follw that we, as cyclists, ought to do the same?
If I, as a cyclists, can chose to disobey the helmet law, for example, can I not likewise chose to disobey the seat-belt law, or the restrictions on speed that have been established for general safety (and, tell me, please, that drivers DON'T break these laws, and most others!). For that matter, what is there to make me obey stop-signs, or red lights; one-way restrictions, or driving on the right of the road, or any other traffic law, for that matter? If I can break any or all of these, what's to stop anyone else from doing the same?
In fact, we DO (as a general rule) adhere to most of the traffic rules - it works in our general long-run favour. What I'm saying of us as cyclists is that, as long as we want to be able to use the public roads as our paths, we have to abide by the rules laid down, whether or not we agree with them