Guns are just about killing. Death isn't an accident with a gun, it's their reason for being.
While Reelya's obviously off on a hate-guns trip with the obvious disconnect from reality... the point is still correct.
So being around rope, medicine, knives, and trains would do the exact same thing?
As someone with a history of bouts of depression, this is true. Deep bodies of water and high places too. But it's about degree. Suicide is a result of calculations made in the moment, and the tools on-hand are a part of those calculations. Guns are by far the most tempting of these options and were the hardest to resist considering, except maybe for high places. But the nice thing about high places is that they are not readily available, and you've got that moment on the ledge where it suddenly becomes very real. Pills, ropes, and guns all lack that moment, which is a big part of why they are so popular. But pills and ropes both have their own problems, as well -
Pills are great if you want to give yourself an out, since they often don't work. Ropes require time and effort and a place to hang them from that can support your weight - not as readily available as you might think, and time is the enemy of impulse suicides (which are the type where available tool matters most).
Guns, though... guns are quick. They are easy. They are reliable, and the aversion at the last moment is minimal. And you can't change your mind after you pull the trigger. I wouldn't find it surprising at all if banning guns led to a sharp decrease in suicides. I don't think you should be either - it's not a particularly surprising fact, if you have any understanding of suicidal impulses.
That said, I don't see it as a valid reason for limiting gun ownership. But I have very... unique views on things like suicide, so I doubt going into that would be productive.
Anyways, hopefully I'll get a chance to post something later specifically New Zealand related.