Well, I am not a caver, but a climber, but know some, who are both. I don't think the difference you describe, exists. Both are activitys which can be very dangerous, but usually those who do it, are smart, because otherwise they would not be alive anymore. I started climbing, beeing not smart. But very soon I started getting smart, because I realised, otherwise I would stop beeing at all or end up paralized.

But there still remains a risk. Just like traffic is dangerous. Also, the thing is, doing the same, safe thing again and again, is boring. You want new experiences, new challenges. Wheter it be a new mountain, or a new cave. But with experience and beeing smart, you can do it quite safely, because you know your limits and the enviroment. But it is never 100% safe. Big rocks can come loose and hit or trap you, or water can come from channels you don't know about. This is life, you can't plan for all events.