Does it really matter that much in regards to the specific context? If someone poses problematic behavior (as it seems, as I'm not familiar with any specifics here), maintenance of a module should be the last of the worries. There are many pieces in the stdlib which remain or have remained unmaintained for years. Maybe someone could pick up the pace, maybe not.
I agree with Charalampos here. I am NOT opining on any specifics of problematic behavior or the SCs actions.
But many module contributors or maintainers become unavailable for many different reasons. We cannot, and should not, rest these broader collaboration decisions on some specific expertise, which we cannot guarantee will remain regardless of SC actions. If needed, hopefully someone else can pick up _decimal. But the same principle applies to any module mostly maintained by anyone else who has contributed. Things happen in people's life, quite independent of CoC issues.