cactus: I'm not sure where do you see any "vehemence", really.  though I'm prone to get peeved about equating type safety with compile-time type safety. :)

compile-time type safety is pretty irrelevant to Lisp, being really a concept from the batch-language world, where the compilers routinely deny your programs the knoledge they have about them.  I'd say compile-time type safety is important where types themselves are predominantly a compile-time concept.  moreover, the term "compile time" is itself less useful in Lisp than it may seem.

anyway, I hope the snippet I gave was helpful.