Chofetz Chaim writes explicitly in Tiferes Adam that the custom is not to allow any type of utensil to cut to shorten the beard and that since that was the accepted minhag yisroel it has the force of a prohibition.
But the Chofetz Chaim is only followed when it fits with our lifestyle! Let’s find fault in others. It makes us feel better than examining ourselves.
(Mainly yeshiva bochurim don’t grow beards. Married sometimes/often do. Bochurim are pottur from all mitzvos till they get marries and start growing beards if they consider themselves gedolim).
And the abridged mincha that the Bais Yossef says is improper (even for sefardim) – who cares!
But let’s point fingers at “those” guys!
Those guys don’t sleep in a sukkah and eat cake before davening!