Has Ubuntu gone case-insensitive?

Dropbox is doing this, not Ubuntu, because it would cause problems if you synced with a Windows machine at some point as Windows is case-insensitive.

From Dropbox help:

Case conflicts

Linux computers allow you to have two files or folders with the same name but different capitalization. However, Mac and Windows won't differentiate file or folder names by case. Therefore, if Dropbox comes across linux directories named "Sample folder" and "sample folder" (lowercase "s"), it will still sync both folders to Mac and Windows computers, but one will appear as a copy of the original file and appended with case conflict.