Insulting the beard is Kufr
Insulting and mocking any minor Sunnah is Kufr, so insulting the beard (keeping which is Wajib and is among the symbols of Islam), for example saying that keeping a beard is the work of the devil, or bearded people tell lies, or the beard is trash and a jungle on the cheeks, or saying that the beard is a goat's tail, will be Kufr to a greater degree. (Aham Masail/Vol:1/Pg:148)