So they do think they're smart enough to not need it. And of course someone who "accepts the risk" assumes they're smart enough to not get caught up in it. Otherwise they wouldn't do it.
You accept the risk you could die every time you step outside -- not because you think you're too smart to get shot or hit by a bus or whatever, but because the risk is so low and you kinda have to go outside to get what you want. Same thing for bitcoin. Sometimes the risk of getting fucked by someone over the internet is lower than getting fucked in person (or by the government), and you just gotta use them bitcoins to get what you want.