Hi,
Because it's used to build packages, which so far have been designed exclusively for
Windows clients.
Theoretically speaking, nothing would prevent Oracle from creating a fresh new
Deployment server based on Linux, gcc compiler, some Linux GUI components and a
local MySQL database instead of MS Windows, MS Visual Studio C compiler, MFCs and
OCXs for GUI and a local MSSQL or Oracle instance.
Why didn't Oracle do it? Maybe because it's not worth the effort (from their point
of view).