Firearms, just like all other equipment, is safe unless you do something you're not supposed to be doing. AD/ND's occur because the operator made a mistake. If they're a good person and just made a simple mistake I won't be malicious towards them, but if you're a jackass who thinks you're THE "Gun God," I'll shove it in your face for the rest of your life. There are numerous safety procedures in place to prevent AD/ND's from occuring, INCLUDING the purchase and maintenance of quality products. Purchasing a poorly built firearm and having an AD from mechanical failure is still the fault of the operator because he failed to purchase quality goods.
There are similar problems in my current field (welding). The equipment is safe, until somebody fails to implement a safety protocol for ANY reason. More people are injured severly or killed (sometimes, several at a time) as a result of welding accidents than AD/NDs.
Anyway, most AD's are preventable, so technically they're "incidental." You're right though, it is wrong to laugh at someone for making a mistake, but it's also wrong to come onto a public forum, initiated for the exchange of information and ideas in order to HELP other people, and refer to everyone as "stupe" or a "punk" or a "dummy." Making a mistake that gets yourself hurt won't force me to laugh at you, being a jackass and making a mistake that hurts yourself will.