Inlcuding countries that were on the verge of civil war, on the end of it, or in the process of it (such as Ethiopia/Erithrea, Mozambique, Zaire, etc.) and countries with some sorts of borders disputes (such Sudan/Ethiopia/Kenya, Kenya/Somalia, Namibia/Angola). Most african countries- inlcuding South Africa- have some sort of trouble from time to time, or somewhere in the past, present and unfortunately in the future too. We all read about it in the newspapers- but only a small percent of the trouble reaches the media in the west.
In those regions, where what we call "law" (and "order") do not seem to exist, it is not a rare sight to see people carrying firearms. Actually, it is not common to see an unarmed men. You can see children not 13 yet carrying guns and grenades. You won't see these things in the big cities (where there is more crime anyway).
And in spite of this, apparently, most people are honest and don't deal all the time with piracy, robbery and killing each other. These things happen- you can read it in the local newspapers- but most of the time people are trying to carry peacefull lives (it is true all over the world).
I don't think you got more chances to be a crime victim in the heart of Africa compared to big western cities everywhere in the world. Just go and enjoy.
Anyway, as ShakaZulu pointed out, Africans have different morality and mentality- western values and mentality, and what we call "common sense" do not apply there.. They live and they think differently (trying not to generalize).
What I've seen in most cases, is fear from the unknown. Africa frightens many people who do not know what's going on there, and consider it as "dangerous place" with wild animals and wild people strolling everywhere. I even get the same reactions when I say I live in Israel.
The truth: the most common threat in Africa may be attributed to the Sun: heat stroke, sun burns and dehydration
So if you go there don't forget sun-blocking lotion, a hat and bottles of Water...