@Stjn, @Izno and I were discussing this use of a silent batch edit by @LGoto (WMF) to close a task as declined. I generally wouldn't expect a silent batch edit to be used to close a task, and especially not a task with a reproducible problem, several subscribers, and a not insignificant amount of discussion with loose agreement that something should be done, eventually. This seems to go against the advice in Phabricator/Project management#Closing a task, and doesn't appear to have been the best action to take.
This specific action isn't really my concern though, rather, I think it is merely a symptom of a potentially larger issue. I looked for documentation on when this tool is supposed to be used, but didn't really find any. The only things I found were Phabricator/Help#Batch_edits, Wikimedia Product/Technical Program Management/Requesting silent phabricator batches, and wikitech:Phabricator#Run_a_bulk_job_silently_(suppressing_notification_spam), which only explain how to use a silent bulk action, not why or when. Silent bulk edits are powerful tools, which is why approval from a small list of users is required to use it. But those actions aren't routinely logged, don't appear in the acting user's feed, and don't appear to be logged in the Phabricator interface as far as I can see. The only way I was able to find a list of tasks closed in this action was by working backward with advanced search. I wasn't able to figure out who made this action silent.
There needs to be more guidance about when a silent bulk action is appropriate. One of the core parts of Phabricator etiquette and the Wikimedia community in general is working in the open. Use of silent edits for potentially controversial actions, like mass-declining tasks (including tasks that had the potential for future work), appears to be evading scrutiny and should be explicitly prohibited. Usage of the tool should be publicly logged, preferably in a way that allows a review of what actions were taken silently.