The reason antisemitism exists, which means specifically hatred against Jews, is because evil exists.
Jew hatred is a form of weakness, cowardice and evil.
Jew haters need a target to hate.
Jew haters need a target to demonize.
Jew haters need a scapegoat.
Jew haters need an external enemy to despise instead of looking inside of themselves.
The Jew hater uses excuse after excuse to justify their hate.
The Jew hater looks for any example, whether fabricated or real, of a Jew or Jews that they think validates their hate and demonizing. Even if a million Jews do a million good deeds, the Jew that does not will be held up as the example for how all Jews are. Even though every human being is unique in their own way, the Jew hater lumps all Jews together as one monolithic entity to be demonized and despised. People as unique individuals and individuality itself means nothing to the Jew hater when it comes to Jews.
Jew haters cannot just live and let live.
The Jew hater is incapable of taking responsibility for their own hatred and actions.
One clear sign of Jew haters are their inability to accept responsibility for anything, and their never ending blaming the Jew for everything.
Bullies are a type of weak, cowardly people that pick on targets they perceive as weaker than themselves. Bullies choose targets they think they can intimidate, demonize or destroy.
The ranks of Jew haters are full of weak minded bullies.
Some people that oppose antisemitism expend enormous energy refuting the endless demonizing. As soon as one accusation or defamation is put to rest, another one takes its place. The Jew hater's obsession with Jews is seemingly never ending.
The hatred against Jews has everything to do with weakness and evil that exists in the hearts of humankind. Unfortunately, too few of the weak minded Jew haters develop the strength and courage to combat their need to hate, demonize, and scapegoat.
If demonizing did not lead to tragic outcomes, namely murder, massacres, atrocities and more, it would be easy to ignore.