Talking points
In 1968 the GCA established (among other things) minimum age requirements to purchase firearms and ammunition. Age restrictions on ownership may be in place in certain states, but there is no Federal requirement for ownership.
In the early 1970s I obtained a pistol permit in the state of NEW YORK at age 18. I know of one case where a permit was granted at age 14. New York law (at that time) did not have age restrictions on ownership, it was up to the discretion of a judge. While I was not legally able to purchase a handgun at age 18, I did have the legal ability to own one.
Both my brother and I obtained our permits at age 18, in Saratoga county. Our rational was that under New York law, the handguns owned by our mother and father would have to be surrendered to the state if they were killed (both had been injured in a car wreck), if no one else in the household had a permit for the guns. Judge agreed, we got permits. The law may have changed since, but that is the way it worked back then.
The '68 GCA imposed license and record keeping requirements for firearms dealers. The "instant check" is imposed on the dealers, not the purchaser. Therefore I believe it does fall under the commerce clause. And therefore is constitutional.
Background checks on purchases between private parties is a whole different thing. As long as it is legal for private citizens to buy and sell their personal property (firearms) without going through a licensed dealer, there should be no Govt. requirement for a background check, because doing so requires the seller to act as an arm of the govt. It is also an unfunded mandate, placing the burden on the private citizen. Bad thing, IMO.
No right is absolute, all come with some kind of restrictions, either codified in law, or by general convention of society. When you exceed the accepted restrictions, you cannot claim exemption from punishment because you are exercising a right. Your right to swing your fist ends at the tip of my nose.
Arguments equating firearms ownership and pornography are distracting, and other than the fact that certain people want one, or the other, or even both banned, they have nothing in common.
Our society's attitudes about sex originate waaaay back (predating firearms), and comes from religion. Sex for recreation, and sex outside of marriage have been sins in the Judeo-Christian religions since the founding of those beliefs. Our country was founded by people who took their religion very seriously. Today the majority of our population is not as serious about religion as our founders were, and our tolerance for sex reflects that. Other societies who do not have our religious history have somewhat differing attitudes about public sexuality. Muslim societies are very restrictive. Hindu is not etc.
Always keep in mind that while we routinely talk of Constitutional Rights, the Constitution (and amendments) grants us no rights. Our rights are natural rights, and the Constitution only specifies what the Govt cannot do.
While, under a strict interpretation, the Govt has for many years gone along way beyond the boundaries of the Constitution, until and unless it is checked by the SCOTUS, or by the citizenry, it is the law of the land. Sad, but true, nonetheless.