I don't think it matters much that it's hard to parse: very few are going to write a parser for that language compared to the ones that are going to write programs in the language. It goes the same for everything else in a language: prefer a fast compiler rather than an elegant (compiler) but slow one.

Ruby's syntax is very short and concise if you compare it to other languages. To know if "x" is a variable or a method you just need to see if "x" was assigned a value in the method, that's all.