I think the misconception a lot of people have about hardcore mode is that people do it for bragging rights, or to talk down to others, or something. This is in no way true.
The real reason to play hardcore is to get to 1% HP and live. The rush you get from surviving is unbelievable. The rush you get from fighting an enemy you're not sure you can beat is amazing. I think the closest comparison is how one feels in high-stakes gambling. The knowledge that you could at any moment lose it all gets the adrenaline going, and makes for an enhanced game experience.
People are also, I think, afraid of being disappointed when they lose their characters. This is another thing I don't get. It's about the same as getting a Game Over in Ye Olde Video Games of the 80s and 90s. You can either rage and never play again or you can stare in disbelief for a bit, laugh, say "You win this time, Video Game," and then try again. Are you going to let that video game get the best of you? Hell no! Roll up a new guy and get crackin' on beating your old record.
The Hardcore community is a nice group of folks who are both good at the game and very helpful to others. Usually when a person says they're new to hardcore, the response is "Welcome to the Brotherhood," "Welcome to the Fold," etc. And it IS a brotherhood. There's a camaraderie that exists in hardcore that you simply don't see in the normal game, and I have made plenty of friends in just the first couple weeks of the game's release - all of them from public HC games.
Also going to Hell and beyond by yourself is just asking to be killed.