There are more similar issues, like disabling foreign key constraints by default "for compatibility reasons". Makes me wonder if there was a time when SQLite supported foreign key syntax, but didn't actually implement the functionality.
From the release notes:
2002-06-17 (2.5.0), "Parse (but do not implement) foreign keys."
At one point there was also a tool which would generate trigger rules to enforce foreign key constraints. (2008 Oct 15 (3.6.4), Added the source code and documentation for the genfkey program for automatically generating triggers to enforce foreign key constraints)