valid question.
We follow in the traditions of all the messengers who grew or able to grow facial hair.
We also follow in the tradition of Abraham pbuh and Muhammed pbuh.
We trim the mustach and leave the beard to grow but to a limit.
I have a beard my very nicely trimed, not very long, I would say 2 to inches long, my english wife likes it.
In one of the ahadith, The beauty of a man is in his beard.
Also to distinguish ourself from the female so there is no confusion
.
We do not despise other muslims brothers of mine. I only encourge them to follow in the traditions of Abraham pbuh.