OS X prefers case insensitivity but TimeMachine seems to require case sensitivity?
The linked answer doesn't say that Time Machine requires ...Mac OS Extended (Case-sensitive, Journaled).... It only says Time machine requires an Apple specific HFS+ filesystem to store backups and it should be read as the Apple specific HFS+ filesystem.

With other words: Time Machine can't backup data directly to NTFS/FAT32 or EXT3/4 volumes.