Can someone explain to me where an aversion to beards might have originated?
Usually, when the Church issues a guideline on appearance, its meaning is obvious from the culture at large.
For example, long hair (for men) was associated with hippies in the 60’s. Tattoos and too many earrings (and any earrings for men) are associated with counter-culture attitudes and rebellion against authority. Modesty stems from obvious attitudes about the importance of covering certain parts of the body, and the ungodly feelings of “lust” that can be stirred by inappropriate clothing.
But I’ve never, ever heard of any negative cultural attitudes towards beards. As long as the beard is well kept, I’ve never heard of anyone being looked down on, or thought badly of. I’ve never heard that the skin of a man’s face is supposed to be shown to the world and not covered by hair.
Styles and trends come and go, and beards seem to be in less fashion these days than in times past, but this is true for many things and the Church seems able to not formulate policies based on such whims of culture.
If the Church had no policy on beards and you were to go to the Temple and saw one male officiator with a beard and one male officiator without, would you think any less or differently of the one with the beard? If not, what possible reason could there be for a Church policy on the issue?