I'm going to try to respond to each one of your points in the manner that they are ordered. First there are many instances across the country of people using their weapons strictly for self defense. There are many people who own guns that have never shot a anywhere other than the shooting range. As long as these guns are handled and stored properly they should never be in the reach of children. The issue of children getting their hands on a gun isn't the guns fault but the gun owners. Currently there are fifteen weapons in my house and i can guarantee no one under the age of eighteen has ever laid a finger on one of them. Proper storage for any gun is essential and a failure to do so should result in the loss of a license to own guns. But millions of Americans do store their weapons properly and have no issues with their weapons either accidentally discharging or a child having access to the weapon.
As scottevil110 pointed out a gun is merely a tool that obviously can be used as a weapon. Many people own guns for various reasons and many of those reasons do not involve killing people. And blaming inanimate objects for a persons actions takes responsibility off the person. The gun can't pick itself up, load itself, and then just randomly shoot someone. A person has to make the conscious decision to do all those things, and they should also shoulder the responsibility. A gun cant make anybody do something that they don't want to, it is just a tool to be used.
Next contrary to most people's beliefs in the majority of states you cant just walk into a gun store and pick out any gun you want and leave. For example in my state there is an extremely thorough vetting process for people to be able to get a license to purchase and carry a weapon. First you must take a gun safety and instruction class and receive certification that you have passed and understand the laws. Next you have to be approved by your town or cities police chief, and they could deny you for any reason they deem fit. Once you have the license you still can not just purchase a weapon. Every purchase there is a background check done against your license to make sure you are eligible to purchase the weapon. So it is not so easy as many people like to act.
I also wanted to point out how large the US and there are different regions of the countries that would need guns for different purposes. If someone lives in an area where there are dangerous animals regularly around their property owning a gun is the only way to protect yourself and your family in the case you are confronted by one of them. I know that when I am at my property in Maine there are black bears all around me in the woods, and no way for me to escape the danger if I came across one. A gun gives me the only fighting chance I have to perhaps survive if I were to confront one. There are people facing similar issues across the country. And many people own guns to simply hunt, collect, for defense, or for target shooting. 99% of gun owners legally own their guns and have not used them in an unlawful way.
Lastly I also wanted to point out that at this point the U.S is too saturated with guns to ever eradicate them completely. Even if they could get everyone to give up their guns, which they couldn't the criminals would still have all theirs. If someone has an unregistered weapon there is no way to track it down and it is still on the streets. So at this point to disarm the law abiding citizens would leave them drastically more vulnerable because criminals still have guns and know the majority of people do not. This creates a potential threat to any law abiding citizen and is another reason why this issue is so complex.