This is actually one of my main reasons for fading away from that bunch. I grow my beard now and have done so off and on since the early 1990s. One of the elders approached me once and suggested that I trim my moustache more along the lines of how elder so-and-so had his trimmed. I asked him why and he said that I should feel lucky to be able to grow one at all. That only Hispanic and Arabic brothers at beth-HELL are allowed moustaches at all. That set me on my research.
I was looking into the facial hair issue and to this day I hear jw's say that "facial hair is WORLDLY HAIR".... I found scriptures that they use to back up their argument against homosexuals. Not far away there are commands to never cut the sidelocks of the head or the beard. So not only are they hypocritical about beards, but about long hair for men too. I know it says it should not be long like a woman's but my length is not flowing and feminine. especially with my beard.
Anyway, now I am growing out my hair again to about shoulder length and I cur my full beard to what the locals here call a PADLOCK (the wt always shows criminals with your style of beard they say).....I say FU** 'EM!
Oh, and to answer your question, I think Rutherford hated beards because they reminded him that he was once little boy to Russell's man.....