Because CamelCase requires you to hit SHIFT a lot. Real Lisp programmers use a hyphen. More readable than CamelCase and less obnoxious than an underscore, although

 call-with-current-continuation

in SchemeLanguage is a bit ugly, so real Schemers use

 call/cc

Any such examples in CommonLisp?

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Hmm, I'm fairly sure that Lisp would use underscores in names if one didn't ordinarily need to hit shift for them.