As a pro-gun-control American, I feel like Irvine and LuckyNumber were being a bit overly defensive with regards to monkeyskin and Axver's comments.
However, given the polarized nature of this issue here, the incredible number of firearms already in circulation and owned, and the role of money and media in politics, it's a very, very difficult and frustrating issue to navigate.
First off, the constitution and the second amendment were repeatedly bought up. That's counter-productive to the cause of gun control in the U.S. To be clear, if we're talking about getting rid of the amendment altogether, the way you repeal a constitutional amendment is by adding another constitutional amendment that basically says the amendment in question is no longer in effect. In order to pass an amendment to the constitution, you need a two-thirds majority in both houses of our Congress. You can't get two-thirds of both houses of our Congress to agree that the sky is blue or that two plus two equals five, much less on something this politically volatile. It's politically impossible, and for this reason, nobody, even those who theoretically have no use for the amendment and would like to see it gone, is ever going to waste any time arguing for it as an actual possibility in the real world. What pro-gun-control people argue for is legislation that puts restrictions on said amendment via law, without touching the constitution.
Second, the NRA, which I believe is correctly labeled a terrorist organization, and other pro-gun groups, not to mention pro-gun conservative politicans, tend to twist any support of politican x for sensible gun control legislation y into an authoritarian desire of politician x to come and take your guns. So if, say, a group of senators support legislation to have stricter background checks, limit ammunition size, have waiting periods before you can purchase a gun, and create a national gun registry, the NRA, other gun groups, and, if those senators are currently running for office, their conservative opponents, will run political ads with doom-and-gloom music and a low voice-over saying, for example, 'Senator x wants to take your guns and prevent you from being able to protect yourself. Defend your freedom, vote against Senator x'. Stuff like that.
And what happens is there are enough uninformed and ignorant people out there that will buy it. So it's hard for even centrist Democrats, particularly if they represent a red state, to support this kind of legislation. That's why it's more often only the further left Democrats that openly support it. Hell, even self-admitted socialist Bernie Sanders wasn't as aggressive about gun control during his presidential campaign as some on the left would have liked because he represents Vermont, a state with a large rural population who likes their guns.
Third, what's not talked about enough is that there are big corporate interests that are against gun control. That's what the NRA is. It's just a lobbying arm of the corporate interests that generate their profit from the manufacture and sale of firearms and ammunition. The NRA does not care about Joe Gun Owner. They work for big corporations. It's not really much different from oil companies doing all they can to slow down the progress of green and renewable energies in order to protect their business. We live in a plutocracy.
Fourth, there are a lot of gun owners, not the gun-toting redneck types, but just regular people like you and me, except who own guns, who genuinely don't think the kind of gun-control legislation the left pines for will actually make all that much of a difference(given all the firearms and ammunition already out there) while at the same time imposing unfair limitations on law-abiding gun-owners who have no intention of doing anything bad. Of course, the counter is that if there's any chance it will make any difference at all, you do it.
Fifth, a lot of anti-gun-control people are also of the type that have a big fixation on freedom and liberty. They see limitation of gun rights as an infringement of everyone's freedom as a whole, and that if you allow the government to keep chipping away at that freedom, eventually none will be left.
Sixth, and perhaps this ties into #5 above, there seems to be a rather nasty strain of paranoia in the right-wing. You can't buy into Alex Jones and the like if you're not a little paranoid already. You can't believe political ads the NRA puts out saying Senator x wants to come and take your guns if you're not a little paranoid already. You can't walk into coffee shops with a machine gun around your waist as if you're part of a militia if you're not a little paranoid already. This could be a factor as well.
It's just a very volatile, emotional, polarizing issue complicated by ignorance, fear, paranoia, and downright immoral behavior on the part of the NRA and the like.
I just wrote a lot, and I don't know if I said anything everyone doesn't already know, but I had to get it out.