I'm guessing because Nim gets portrayed as safe, or offers some safe features, but overall is not memory safe. Rust has worked very hard and gotten through the problem of having memory safety, with zero runtime cost and reasonably good language features.
Since it's 2015, it seems fair to point out when a new language offers something neat, but in a way that isn't safe.
Since it's 2015, it seems fair to point out when a new language offers something neat, but in a way that isn't safe.