and don't forget:

Around her neck she wore a yellow ribbon.
She wore in the springtime and the winter, so they say.
And if you asked her why the heck she wore it,
She wore it for her lover who was far, far away.

and then there's:

Tie a yellow ribbon round the old oak tree (that pop song by what's-his-name.)

So there's a minor tradition that yellow means remembrance. However, let us think about the names of colors:

white
black
tan
green
pink
red
blue
turqoise
yellow
orange
purple

Note how many have one syllable. If you need two syllables, as is often the case, you have to take yellow, purple, orange, or turquoise. Of these, purple is comic (Flying Purple People-eater), orange is ugly to sing, and turquoise is twee. That leaves yellow.

Decorator colors (mauve and chartreuse) don't come into it.