I think what you really mean is that Smalltalk has a very rich class library. This is one of the reasons why Smalltalk is so powerful. Yes, a developer needs to learn at least a portion of this class library which may appear daunting. But this is no different from other languages that rely on a “standard library” in order to be useful. C is a prime example. Every C programmer must learn stdlib and stdio, which contain hundreds of functions!
Ditto for Rebol, a language with no keywords at all. Everything in Rebol is user-defined (or system-defined) and there are hundreds of language extensions.
Java and Ruby have rich class libraries, too. I could go on and on. Programmers must be prepared to learn a lot about a programming language beyond just the mere syntax.