The community account was created on February 2020.
Monomad is running since 2017/18. It started on that other chain we shall not name, lol.
The Hive ecosystem keeps evolving and so does what's acceptable/supported or not.
As a photographer the single images never bothered me at all either, as I understand what's behind a good photograph, but curation projects have another point of view regarding that, and regarding the type of content they want to see and reward in Hive. It was a necessary change and adaptation.
Besides that, single image posts are normally published by spammers/farmers.
Not saying there are not some good photographers doing it too here and there, but unfortunately that's the exception and not the rule.