If you read the longer conversation about the subject [1] on the scala contributors community board, there is no explanation. The people responsible for making the ban refuse to bring up any specific Code of Conduct related reasons why the removal took place. They point to non-answers and ad hominems, but don't answer users posting statistics on how frequently these projects are used across Scala codebases. They state that they won't bring up specific references to misconduct but ask that we believe that it was there with absolutely no proof. It is petty infighting with no rhyme or reason.
[1] https://contributors.scala-lang.org/t/coc-compatible-communi...