Summary
As discussed by @jmergy and me today (and earlier in the day by @bickelj and me):
We have to assume that things will happen in production that we later decide were wrong. There has to be a way to correct mistakes, and that will sometimes involve "deleting" data. We currently don't have DELETE endpoints for our entities because the PDC is, after all, about preserving data. So we need to think about what DELETE would actually mean: maybe something like "change the status of this thing to archived | inactive | trashed | forbidden | whatever you want to call it". We could also associate a reason code or comment with each such action.
Further thought, discussion, and design needed. This ticket is where we'll hang those hats when ready.
Related tickets: #1414, #1443, #2045, maybe #1827.