Much evil has its origin in the sweeping generalities people are prone to make with regard to their fellow human beings. The categorisation that often occurs unconsciously and is seldom supported by facts comes far too easily to the primitive aspect of the human mind. Where once in our evolutionary history such a prejudiced 'in-group/out-group' classification mentality served to protect the group from potential enemies competing for limited resources in a harsh environment, in more materially secure times this very same attitude can be an obstacle to goodwill and peaceful co-existence between people from different cultures.
What many people, especially those apt to callously toss out catch-all statements, fail to realise or admit is that generalities are ultimately inaccurate, since they fail to take into account the subtleties, idiosyncrasies and the inherent differences among individuals. Intellectual honesty compels us to acknowledge that the only reason we resort to generalities is purely for convenience. It's expedient for one trying to make a point about a certain 'collectivity' of anonymous people to simply blanket them with a blithe generality. That way one is spared the effort in considering the exceptions to the rule, the complexities, the nuances, the individuality of the persons in the targeted collective. And chasing after expediency for its own sake has often birthed poorly thought out decisions with tragic results.
What is needed is for us to develop an aversion to generalities and recognise that proper evaluation and judgment applies only to the ideals, beliefs and actions of individuals. Appraise the moral character of the person instead of that of his arbitrarily assigned 'group' that he supposedly belongs to. This applies even if he himself subscribes to the notion of being a member of such a group. His error of reasoning need not be ours.