Ibn:
In addition to what Salika said, the other reason why black [and black only] is forbidden is because its deceptive. You're giving others the appearance that you're younger than you really are because you're implying that your hair is still naturally black.
Which leads to the obvious question: Is cosmetic surgery halal? I always thought I'd give that option to my [future] wife if and when she wanted it after like two decades of marriage and having a busload of children.
I read
Salika's explanation, which I don't particularly agree with. But in terms of your post--- this is why I said that I figured it to apply to those who are visually old looking. How is it deceptive if a young person, who is also visually young as well as biologically, dyes his hair black to cover a couple grays? That doesn't make any sense eh.
No matter. I have no problem agreeing to disagree.

shadha-
__________________
You may shoot me with your words,
You may cut me with your eyes,
You may kill me with your hatefulness,
But still, like air, I'll rise.
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