I dunno. Maybe so the people can protect themselves from the government https://www.channelnewsasia.com/asia/first-killing-police-sri-lanka-protests-2634566
Let's compare 4 different countries. USA, UK, Australia, and Canada. In UK, Australia, and Canada, police are able to easily take people's rights and illegally search people's homes with no problem. We see it in the news pretty often. Most people do not question it because all you can do is go to court. You cannot resist police. Contrast that with USA. In USA, police have to be very careful in serving a warrant even for searching a home. The reason being is that the people in the home can be armed. The people do not need to be a threat. There just needs to be the possibility that they could be armed that now police have to exercise caution. Other countries' citizens are not so lucky.
Also, firearms are a good measure of self-defense. An argument can be made that it's not necessary, but an argument can also be made that it is. If your life is threatened (it doesn't matter by what), you have a reasonable expectation to defend yourself with a firearm. They could have a car, a baseball bat, a knife, a chainsaw, whatever... It doesn't matter. If your life is threatened, a firearm is a reasonable method of self defense. Saying it's only good for war is silly.
You talk like there is a civil war, that's what one would understand.
There's no war, but if you follow @lukewearchange, then you know every day someone is trying to take your rights. In USA, the 2nd amendment was created second because it stands in defense of the 1st amendment. Once the 2nd amendment goes, then so goes the 1st. The Constitution won't stand without its foundation.