Haven't read the whole thread, but I would say that the biggest problem isn't the ease of access to guns, but rather the nation of sociopaths we have become. It is engrained into us from birth, and through the media, tv shows, music, etc. We have become a me, myself, and I society, and it is getting worse generation by generation. I see it every day at schools and whatnot. And I firmly believe it all stems from shitty parenting and shitty parenting laws. We coddle our children so much now days, and tell them they are unique snowflakes. We shield them from everything in life, so when they do actually get pain us parents cant shield them from, they don't know how to cope, and opt for the easy way out, or lash out, etc. Kids need structure and discipline. But our society has become where it is unacceptable to punish a child with anything more than a few minutes time out. I once had a social worker that works at my hospital where I work, tell me that she thinks grounding children should be considered child abuse because it damages them emotionally. Didn't she stop to think that maybe some of that emotional "anguish" they go through for being grounded a few days, is actually teaching them something?
Just watch some of those wild kid nanny shows and you'll see. It's just like a dog or anything. You need discipline or they become wild with no qualms of biting, etc. Everyone is born a sociopath. We are taught to not continue to be one. We'll our society has put in place laws, and stigmatized the most effective methods of preventing it. There are always going to be shitty parents who wont raise their kids properly, but I truly believe this is the root of our problems and why it gets worse each generation, and why you don't generally see mass shootings from older people who grew up in different generations and were taught morals and good will towards others, etc. People who learned actions lead to consequences and grew a conscience. Guns don't kill people, people kill people. Guns are merely a tool to carry out their shit, that is the easiest accessible one right now. Take that away, and the next most accessible becomes the new method of choice. Drive over people on a busy sidewalk, etc. Then what, ban cars? Throw a bomb in a packed movie theater? Then what, ban anything explosive or flammable? Obviously there are evil people in this world, that will do bad things, but that's life, you can't make every person be "good" but what you can do is try to identify what causes it to try to minimize it.