That's really overstating it, especially seeing as Lisp has barely existed for half a century, and people like ESR call it "LISP" to this day.
Much like Fortran (no longer FORTRAN), the acronyms became proper names in their own right.
CL-USER 30 > (eq '|LISP| '|Lisp|)
NIL
Common Lisp knows very well the difference between LISP and Lisp