One of the things that is so frustrating about this debate is that there are so many arguments that are not simply things I don't agree with, but are just plain false.
I have a tiny bit of respect for the slippery slope variations, which are "They will take all of guns if we let them ban semi-autos". To be fair, there are people in the United States who would like to ban all guns. They have no clout, and it won't happen, but I can at least respect something about that argument.
However, any variation of "A Brown Bess can kill people, so there's no point in banning AR-15s" is just stupid.
And any variation on "I can kill lots of people with ordinary guns, so there's no point in banning fancy guns" is twice as stupid.
And any variation of "If you don't understand enough about guns, your opinion doesn't count" is unworthy of mention except for ridicule.
So what's left, after the stupid ones? There's "Since you can't get rid of existing guns, there's no point in banning new sales." I don't think that's ridiculous, but I do think it's wrong. It often includes a variation of the "perfect solution" problem, which is that since it won't work perfectly and immediately, there's no point.
There's "Criminals will still get illegal guns, so guns shouldn't be illegal." Again, that's not stupid, but it ignores that a lot of people aren't planning on being criminals when they buy the guns, and wouldn't have become mass killers if they didn't have access to the guns. It also ignores the way that the proximity to the guns in their possession actually fuels the violent fantasies that are sometimes enacted.
I just wish that some people could try to support an argument that is of the form, "I need this weapon because....." and then follow it up with something other than surviving an apocalypse, fighting off a tyrannical government, or getting into a firefight with gangs. None of those things are going to happen.
ETA: As an aside, the reason that this time, finally, I got all riled up about this one is because, this time, there was enough public support for gun control that politicians felt they needed to do something, so we might finally get......MORE GUNS IN SCHOOLS!!!!!!!!!!!!!!!!!!!!!!!!!! No. No, I do not want that.