That's one way of looking at it. But they can also be looked at from a different viewpoint, which is that the amendments in the Bill of Rights are written to restrain Congress. Thus, for example, the First Amendment says "Congress shall make no law ...", not "Congress and the several States shall make no law ...". It states the rights preserved under it from the viewpoint of what Congress is forbidden to do. Now, it has been the position of the SCOTUS in many cases that the limitations on Congress also apply to the several State governments, but not always.
In fact, I've even seen it argued here on FR (during church/state separation threads) that the First Amendment allows states to support established churches, barring only Congress from doing so. After all, there were established churches supported by some of the states at the time of the Constitution. While Americans today would view that as outrageous, it was not so at the writing of the Constitution. Gradually, it has become viewed that the rights conserved (not granted!) by the Bill of Rights should also be conserved by the States, and that the Federal government should be the guarantor thereof. But at least in the case of the 2nd Amendment, this is not universal.
So, after spelling out what the Congress cannot do in the first 9 amendments, a catch-all was put into the 10th, to finish the job, and it made sure to make clear that both individuals and the states had rights that the Congress didn't. The states thus are explictly told that they have rights that the Federal government does not. Gun control would seem to be one of these, at least in the opinion of the Supreme Court.
My personal opinion of gun control, by the way: no non-felonious citizen should have any restrictions placed on either handgun or long gun ownership. Restrictions on automatic weapons are fine by me, as I think that in general that makes me safer (I see the likelihood that a criminal or nut would get ahold of and use one far greater than the likelihood that I'd need one to defend myself). When the Founding Fathers considered the issue of guns, they had no clue that anyone might be able to buy a gun that could kill a score of people in as many seconds.
I would tend to disagree, as the First is the only one to put a specific restraint on Congress, wheras the Fourth, for example, does not mention at which level the prohibitions apply.
I wouldn't be so sure of that. By that statement, you fall right into the trap of the commie gun-grabbers, who will argue that "you can't own nuclear weapons, so we can therefore limit what arms you can own, up to and including a total ban."
You make it sound like the Court just made this up out of thin air, when in fact it was introduced via the Fourteenth Amendment. If anything, the Court as been insufficiently consistent in taking this position, as the clear intent of the amendment drafters was to incorporate the individual rights (it simply never occurred to anyone in those days that another interpretation was possible) recited in the First through Eighth Amendments.