A regulation is "a rule prescribed for the management of some matter, or for the regulating of conduct; a governing precept or direction; a standing rule." A regulation made by government is not a law, properly defined. Whatever a law might be ("rule of conduct imposed by authority" is one definition which would be widely accepted), where it is man made law, it ought to be, we might all agree, at least that which is passed by our democratically elected representatives. Very often, indeed most often, the legislative act empowers the bureaucrats which are to see to the implementation of the "law" to make regulations which would fit the general definition given, viz., for the "management" of the law. Thus we have "unelected" bureaucrats who make governmental regulations, versus our elected representatives. Regulations made by bureaucrats (for their ease) under the authority of a particular act, are, neither made openly like acts of the legislature, nor are they published and distributed in the same way. This domain of "government regulation" is a vast area of law, hidden and dangerous. More than enough of it -- effects the substantive rights of citizens.
Now, mind you, any citizen might, with enough money and perseverance, go up against government, test "a regulation" before a court of law, and, I believe, in the majority of instances, the judge would throw the offending regulation out the nearest court window; but the realization of what a judge would likely do with most of the regulations of government does not deter it from grinding out regulation after regulation, much of it harmful to our fundamental rights.
Thus, the principal objection any of us should have against many of the government regulations (God forbid that the general public should get to see through all of this) is that it is not law passed by our democratically elected representatives. Any LAW I student will till you that a regulation must be in the spirit of the legislation under which it is created; and, in addition, it must not effect, in any substantive way, the constitutional rights of any citizen.