That is to say, just as women must guard themselves and their adornment from non-mahram men, men too must guard their adornment from non-mahram women!
In other words, men too must observe hijab, chastity and modesty; any adornment in men causes them to keep themselves away from the gaze of non-mahram women! That is, a man should not expose himself to display or show himself off before women.
The subtle point is that if adornment extends to shaving the beard, it is as though the man has removed his hijab.
Just as men fall into sin by looking at non-mahram women and their makeup, women too fall into sin by looking at non-mahram men and their adornment—from sins of the heart to other levels.
Adornment in clothing, cosmetic grooming specifically of the beard and hair, the use of colour and oil on the face, hands and other visible parts, showing off the body, softening the tone of the voice in an alluring manner, a particular way of walking, sitting and rising, and sporting displays and so on—all count as instances of adornment.