This is actually a feature, not a bug. Currently all dependencies are displayed in the tree, not only those active. The condition only gets checked while building; you can check that Sql is not actually compiled / linked.
The rational was that these conditioned packages are often important to the code, take as example PdfDraw, which is included to Draw if POSIX to allow cups printing. It seems more logical to see all the code for all the platform even in Win32.
That said GRIDSQL flag in this particular situation is quite confusing. I will check whether it could be resolved somehow.