[samth]

Very few people I know doing real work in Racket have a SLIME-like workflow. In general, Racket discouraging this style is related to us being a bunch of professors, but not really in the way you say. Instead, it's because it's not possible to give a sensible semantics to the top-level, especially in the presence of macros. We care a lot about macros, and we also care a lot about sensible semantics, and thus the attitude towards the REPL. The slogan in the Racket community that "the top level is hopeless" expresses this sentiment.