Why are Jehovah's witnesses not allowed to grow facial hair (beard)?

[Evacuated]

Interestingly, the brother giving the public talk at the meeting I attended this Sunday past had a beard. Not an eyelid was batted!

[Γιαννης Διαμαντιδης]

Good for you! So In Greece we keep other traditions... the traditions of the watchtower publications ?

[Evacuated]

Must be your own.

[Witness]

I think it's best to remember scriptures when approached by such an "arrangement".  

But the LORD said to Samuel, “Do not look at his appearance or at the height of his stature, because I have rejected him; for God sees not as man sees, for man looks at the outward appearance, but the LORD looks at the heart.”  1 Sam 16:7

And He said to them, “You are those who justify yourselves in the sight of men, but God knows your hearts; for that which is highly esteemed among men is detestable in the sight of God.  Luke 16:7

It seems rather "worldly" to impress upon another how one should appear.  Would it be the lust of the earthly things by presenting a "beardless" image, instead of presenting the image of sincerity of each one's heart?

"Do not love the world nor the things in the world. If anyone loves the world, the love of the Father is not in him.  For all that is in the world, the lust of the flesh and the lust of the eyes and the boastful pride of life, is not from the Father, but is from the world. The world is passing away, and also its lusts; but the one who does the will of God lives forever. "  1 John 2:15-17