Really depends on the urgency of the task I'm working on.
Crunch time: hardstyle/hardcore for the mindnumbing tasks (early 2000s compilations), folk (like Heilung - to get in figh-or-flight mode), or percussion (Slagerij van Kampen is awesome!)
Chill dev-days: Piano guys, jazzy/country/classical playlists, trippy stuff like Shpongle or dead can dance
Not an expert, so I can only speculate, but maybe their scaling system doesn't handle scaling down well? Or maybe they log visitor requests to private subreddits and it overloaded...
Or they are lying to try and make the strike look bad