Can you even grow a beard? You do that much woman like whining and moaning, I would of thought all your testosterone had been replaced by estrogen.
You're trying to find answers that arn't there. You can't have a full grown, uncared for beard, because they do look scruffy (yeah, I know you've been told that) but that is the reason. It's no good getting your panties in a bunch and shouting "I refuse to accept that! I demand more answers as to this inequality!!", because the answers simply arn't there.
In any case, have you actually checked "most workplaces?", because to the best of my knowledge a beard is perfectly acceptable if neatly trimmed.
And to be honest, it's no good citing "well women can do this...", because first, it's a trite childs arguement and second, well the only comparison I can make is this :
If a woman grew her hair, and refused to put a comb through it, or wash it, she would be in the same position as a man with a fulll, unkempt beard.
Honestly, is it really that important to have a beard? I've always thought men with beards look slightly tosser-ish anyway.