Okay, I get that. But I see two arguments being used here that I think should be made more clear, because they're quite different.
On one hand, you may say that guns make us safer. That we need guns because the robbers will have guns anyway, and allowing citizens to have guns will lower the mortality rate. (You didn't say that in the quoted post, but the message is present, I think)
That is a statement of practicality, it is an assertion with a factual answer. It either makes us safer or it doesn't, and studies can tell us whether or not it is true. I've seen conflicting information on the subject, and I'm no expert on the matter, but I think the general consensus is that homicide rates are not significantly changed across countries depending on their gun laws. But this isn't as interesting to me as the second argument.
The second argument is one of human rights. That each citizen has the right to protect themselves. This is not a factual assertion like the first. It is an appeal to human rights, and I'm much more apt to buy into this one.
Just like Freedom of Speech may or may not benefit the economy, but we should keep it no matter what. Even if it were the case that as a whole the 1st amendment caused us economic damage, we should still have it. On the grounds of basic human rights.
A mini-debate on what constitutes a human right, and whether gun ownership is one is non-trivial, I think. But I'm certainly more apt to buy that one. I'd say I'm leaning toward saying yes on those grounds, but hadn't thought it through (nor heard a dissenting opinion) on the matter. For example, we'd need to have a conversation about slippery slopes. Weapons ranging from sticks to atomic bombs, which should be allowed for citizens to own, and which should not? Where do you draw that line, and on what grounds?