There are a number of issues at play here. As you point out, there is a legal position, but there are also social and moral mores. Just speaking to the social element, some people are a little presumptuous that their right to carry trumps all. Only a few times in the last several years has anyone been gentleman enough to ask if I mind if they join our group with a gun in their possession. I think that takes one helluva good person to take into considerations how others feel about having a firearm present. It's the asking that matters. In all cases whereby I was asked if I'd mind, I knew the gun owner, knew they had been well trained, and didn't mind.
Now, it is my personal opinion, and hopeful wish, that someday our governance will require all gun owners to meet some level of testing standard before being granted the right to carry. We do it to ride motorcycles, fly planes, and even if you want to wax someone's back hair for money, you have to be certified to do it.