That is about as intelligent as saying I don't need a seatbelt in my car because I drive safely. Many people utter words like that too.
Perhaps it is simply something people want to believe in. They don't want to believe they can be the next victim. They want to believe everything is under control and they are master of their own faith. If you realize how much is out of your control it would be all too depressing to know how screwed you are going to be if you developed serious health problems, getting into serious accidents etc in the US. There is little safety-net to fall back on.
I have a good job today, but I have period mental problems. I do worry about what would happen if I suddenly couldn't hack it anymore. What do you do when you got small children to provide for and you get screwed up in the head? Fortunately I know that because I live in Norway and not the US, there are limits to how far I can fall. I will never end up on the streets with my kids. They will still be able to go to good schools, and university whatever happens to me. That takes some stress away.
I can not begin to imagine what it is like struggling in America and knowing that if you can't work, your whole life is over and the future of your children.
It is surprising why American's don't want a proper welfare system. People buy insurance for their car and house. They buy health insurance. I pay higher taxes than Americans but I view that as the cost of having airtight insurance against the mishaps of life.