Teacher S333:
It is in human nature to have disagreements with friends, family, neighbours, co-workers, and even strangers in the street. That has something to do with the level of spiritual attainment of the individuals acting as the aggressor, where relatively low spirituality causes the aggression.
Collective aggression is another matter altogether though, for it is unusual for a collection of people to become aggressive at the same time and about the same subject, unless it is planned by a leader or supervisory group. In such circumstances there is usually an ulterior motive for that individual or group to plan collective aggression, and this is largely to do with money, greed and power, tinged with secondary but no less powerful motives connected with sex, drugs, murder, torture and related matters.