I want to know what would you call those people in Afghanistan who have shaved their full beard? I heard that shaving a full beard is like killing a brother.

Praise be to Allah, the Lord of the World; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Shaving the beard is contrary to the orders of the Prophet (Sallallahu Alaihi Wa Sallam) who ordered Muslims to grow beards and not to shave them. This is reported in many sound Hadith. In fact, shaving it is against the way of the Prophet, his companions and their guided successors.
There is no difference over this rule between shaving a big beard or a small one. But no Muslim scholar - to our knowledge - has claimed that shaving the beard is the same as killing a brother. In fact killing is much worse than that.
Allah knows best.