I think there is a lot of truth to the statement, but not to the extreme. There are implementation issues for many claimed features, some because large and in your face, some edge cases, others due to language design.

The situation is better and greatly improving. Many things have a work around. It is just one of the problems with a language full of tools and little full-time man power. Java and Go are rather simple languages so there aren't as many features to boast (e.g. not supporting shared libraries is a feature of Go, yet "broken" in D [lots of good work in git HEAD])