Common Lisp doesn't have full static type checking, and very little polymorphic type checking. Only one Lisp compiler (and its derivative) can even do something that's remotely close to static type checking, and even then it's woefully incomplete.
Yeah, it was wrong to say that Common Lisp has static type checking, as it's not part of the standard, and I'm not familiar with many implementations.
All I really know is that when I've programmed with SBCL, I've gotten useful type checking warnings at compile time.
I agree that static type checking is very useful for less stressful refactoring, and so on, and I'm a huge fan of Haskell. But I think very simple kinds of type checking can often be enough.
The argument was that Lisp lacks types to such an extent that building large Lisp systems becomes very difficult (due to the lack of typing). Well, there are lots of large JavaScript systems these days, and Common Lisp, in my experience with SBCL, provides at least more compile-time type checking than that.
It's nowhere near Haskell/ML, or even C/Java.