The Grant Metrics URL scheme is like /programs/Women_in_Red/February_hackathon This is analogous to how MediaWiki pages work. You can't have multiple pages with the same title. Event names don't have to be unique across all of Grant Metrics because in the URL they are prepended with the program name, so collectively it's a unique URL.
I take it (at least as an illustration) there may be a different organizations entirely that wants to start their own Women in Red program and series of events. Here they can't because the name has already been taken. Additionally, they don't have an easy way to check what is available.
The consensus is to redo our URL structure to allow for programs and events that have the same name.
Related: T204973