This question has been asked online and in Apple discussions, for some years.
And the answer is, the folder text color is system-owned; seems it may also be
encrypted at some level not normally accessed. Anyway, there is a folder in the
system hidden that is not the usual thing one may suspect. Some, discussed in
few results https://www.google.com/#q=OS+X+change+text+color+in+Folders
You can 'tag' the folder title, so a colored Spot will appear before the text.
Used to be, you could change more. By use of control + click (on highlighted
folder) a menu including colored dot 'tags' appears. If you choose to add one
& then find it worthless or color isn't you, click the same color to evaporate it.
{This did nothing for me.}
What I've done, is place a custom folder in the Dock, and put all the other 'items'
that I'd want accessible on the Desktop, into that folder. You can then arrange the
content to appear in several ways; as a list, icons, not Stacks, & so on.
Before the Dock included 'documents' and 'downloads' folders, I had made my
own; in part to replace the missing pre-OS X menu that later appeared as Dock.
A sub-menu, is what you sort of create, by hopeful change of settings, to allow
a folder (original can be hidden in your user folder) and drag it into Dock, to
create something formerly known as a symbiotic link, to some. ~ Mine's a List.
In there are Aliases to applications, so as to not fill the Dock beyond capacity.
With your Folder in the Dock, the color of the folder text matters not. Any color
of the Desktop Finder background will not affect what isn't on there. Since I'm
using an older (shipped with Late 2012 Mini i7) Mavericks 10.9(.5) some feature
or the other may have changed. Am considering El Capitan on new partition,
so as to not inflict pain on the old Mav by rebranding to El Cap, or mO'Sierra.
Anyway you may be able to locate the internal files and change the system default
for folder title text color, especially when presented in Finder desktop. Other folders
are default Black; so the Finder default to White is something to look out for/change.
Not sure what kinds of troubles you can start by changing stuff via Command Line.
Be certain to have a pre-exploratory backup of your system; maybe even a Clone.
In any event...
Good luck & happy computing! 🙂