I think this proceedure belongs in the same area as any other 'enhancement' - it's not about what you look like, it's all about what you 'think' you look like.
For women, basic appearence enhancements - make-up, jewellry, nice clothes etc. are considered perfectly acceptbale, wheras in men, they are still (although attitudes are changing as generations move on) - considered to be frivolous vanity.
If I had enopugh hair, I wouldn;t think about dying it, because i think unless it is done very very well, and updated often - it will always be obvious, and look faitnly foolish - even Sir Thumbs Aloft got it badly wrong!
I appreciate the confidence that allows me to care less about my physical appearence as I get older, but not everyone is that fortunate, and i would never decryy anyone's right to make themselves feel as good as possible about themselves.
If it's being done to appeal to a lady - don't bother! Women appreciate men for who they are, not what they look like. If you are old enough to be going grey, and you think your wife / partner is bothered by it, you are with the wrong woman!