Su’louk [plural sa’aleek] is a word that was used - in pre-Islamic times - to describe marginalized people who belonged to an insignificant tribe or an unimportant village.
Some people have created a form of fiqh called Al-Wilaya wa Al-Bara’a [the submission (to a leader (wali), group, ideology, etc.) and the disassociation (from others, society, family, etc.)]-
Al-Welaya wa Al-Bara’a concept is based on a verse from the Qur’an in which God asks Muslims not to associate with Jews and Christians. They took the verse out of its historical context and interpreted it. That is why their interpretation of the verse is incorrect.