There is no greater chasm for the human soul to cross than that created irrationally and unfairly by the power, will, perceptions and opinions of others.
The elementary school student with the wandering eye, chided by his peers, knows alienation. The lone proponent of an unpopular view or theory (even when true and sometimes especially when true), knows alienation. The voice of reason in a sea of hatred and lies knows alienation. But sometimes alienation is an illusion, shaped and formed by an especially malevolent power structure to keep their tenuous, unjust grip on the reigns of control. If one powerful person tells a group that "the people" consider them the enemy, then that person not only reduces the target people to a single mass, but alienates them from some preferred whole of that mass they are separated from.
Alienation is not an incidence, and it is not a simple hiccup in the history of people and cultures. In fact, the noxious stream of alienation flows into the tiny seams between otherwise closely related people and erodes the human landscape into massive canyons of misunderstanding, occasionally filled by oceans of hate, and otherwise slowly eaten at until entire vistas of the landscape become scarred pits of forgotten good, lost opportunity and potential greatness. Years pass and new "enemies" are found, and the erosion grows.
The most insidious part of this process is the seductive comfort of hiding within the greater whole of whatever preferred mass some "other" group is being culled from. It’s an illusion. Streams of alienation change direction, canyons cave inward, and people are washed away. Keep in mind the words of Martin Niemöller, who wrote, "First they came for the communists, and I didn’t speak out because I wasn’t a communist. Then they came for the trade unionists, and I didn’t speak out because I wasn’t a trade unionist. Then they came for the Jews, and I didn’t speak out because I wasn’t a Jew. Then they came for me and there was no one left to speak out for me."
And… Think accordingly.