If we define antisemitism:
“When a person believes that their life is unsatisfactory, they become mortally jealous of another who believes their life is;” we suddenly understand, how there are even (rachmanah litzlan) Jewish antisemites.
This is the same cause of bullies.
The simple solution is, that firstly, we need to ensure that we ourselves God forbid don’t become resentful, for if we do, we too (for it is a psychological phenomena that affects ANYBODY) can become (rahcmanah litzlan) antisemites, bullies, evil etc.
Secondly, the answer is very simple – nothing intellectual will argue away antisemitism – there was a German who wrote an encyclopedia about Jews, hoping this would convince Germans to rid themselves of their antisemitism and we see how well it worked, Nebach!
The only, again, the only way, to help an antisemite, is to show him or her unconditional love.