> But why this is win32 specific?
> 
> Is it because windows cannot fork(), so data has to be copied through
> the pickle mechanism?
> In this case let's remove the "if win32" statement, and always execute
> the body.

Yes, on Windows pickling is needed to pass data to a child process.  In
other contexts these objects are NOT picklable because you would have to
worry about garbage collection of the original object before the copy is
rebuilt by the other process.  On unix pickling will always fail even if
it "if win32" statement was removed.