Maybe. But given the culture at most of these places I'd expect the junior to be explained that it's ok, everybody makes mistakes. Some engineering manager is probably sweating bigger buckets over their failure to properly secure casual human access to prod stuff, which is definitely not ok. Meanwhile the both of them are really really relieved that the notification contents were completely innocuous and not some sick inside joke that would have been massively offensive out of context.
The only cause for outrage would be if someone got fired for what appears to be an honest mistake.
Unless its the CIO/CSO for shite secret management policies.
No, the process failed. They should NOT have access to prod API keys.. It actually shows how ABnB treats security of prod secrets.
Access to a web app that can send push notifications to all users is not access to prod secrets.