You are missing my point: that the language isn't the key part here, its the programmer. If a programmer doesn't adhere to some sane formating and code structure, it won't matter what language they write in, the result will be spaghetti.
No you're missing the point, the point is that the "formatting and code structure" conventions haven't been developed for scala the way they have for java over many years.
It's really easy to write insanely convoluted and unreadable code in any language. The language isn't really the factor there, more the programmer.