Programming is only a very small section of DaniWeb ... there's Windows/mac/linux technical support, and Internet marketing, and job offers, and a webmaster marketplace, etc. It's just not feasable to tell people "well you can select from these colors for code and these colors for non-code" ... So the colors that you allow you have to be prepared to allow whether in code or not. So while yes, links typically aren't going to appear in code, which is why they're one of the colors used to do syntax highlighting, it just isn't feasable to expect everyone to not use them outside of code if they're made available. Quite a few regular members come to mind who use blue for regular text.
As far as non-code colors, there really is no reason to use color. Color is here to assist in the comprehension of posts. Not using color in posts doesn't deter from their comprehension at all. You can emphasize your point just as well without it being in light grey ... it will just be a lot easier to read when not light grey

If there's a particular word or phrase you want to emphasize, use bold. It's a whole lot less annoying to everyone who has a hard time reading multicolored text.
To quote tgreer, "A properly constructed, punctuated, grammatical sentence needs no additional formatting. No word in my above sentence needs to be bold-italic 15.5pt orange to make sense."
Moving on ...
> but in the last few months color was re-enabled in the signature
Actually, I had just forgotten to set the no color for sigs option for the Staff Writers usergroup, so when you were promoted to staff writer ...

Even I haven't been able to add color to my signature in a very long time.
Also, not sure why you get the full color palette in the wysiwyg editor. What page is that on? You might be caching the JavaScript file.