Oh please fuck right off. How is saying "I had a bad experience with this community so I'm going to use a different programming language now" dangling anything?
The dangle is this sharing of X with the world. If whatever they were writing was private, nobody would have cared, and they'd have known that enough not to bother dangling it.
Second, he had already publicly talked about doing a project in Rust. Should he have ... somehow avoided making it public that he was changing what language that soon-to-be-public project uses? How would that work?