In which way for example Siebel's PCL is "walking on eggshells"? On Lisp? PAIP? Am I super obtuse and missing some very obvious and important point they are tip

In which way for example Siebel's PCL is "walking on eggshells"? On Lisp? PAIP? Am I super obtuse and missing some very obvious and important point they are tiptoeing around? Even if one does really think it's important to convey they are presenting superior technology, it can be stated clearly and concisely without sounding corrosive.