People don't seem to understand anti-semitism. They think it is just another form of racism but it isn't. Racism is based on the physical, primarily with the body and the characteristics of the body but anti-semitism is based on the spiritual. It was created as a tool by Hashem to guide us back to the right path.
Hashem sent us into the galut for a purpose and a mission but when that mission is over we don't have the choice to stay, we must return to Hashem and our homeland. Hashem causes the goyim to favor us in order to help us fulfill the mission. But inevitably we get too comfortable in the galut and mingle with the goyim. When our mission is finished and it is time for us to leave we don't want to so Hashem turns their hearts against us so that we will separate and leave.
And it was, when Rachel had given birth to Joseph, Jacob said to Laban, "Grant me leave that I may go to my place and to my land.(Beresheit 30:25)
We understand from parshat Vayeitzei that when Yaakov had finished his fourteen years of working for Lavan and Yoseph was born, which made it safe(from Esav) to return home, he wanted to leave. However, Lavan convinced him to stay for another seven years.
Later in the parsha, we read;
Then he heard the words of Laban's sons, saying, "Jacob has taken all that belonged to our father, and from that which belonged to our father he amassed all this wealth." Jacob also noticed Laban's disposition that, behold, it was not toward him as in earlier days. And Hashem said to Jacob, "Return to the land of your fathers and to your native land, and I will be with you."(Bereishit 31:1-4)
On a subconscious level the goyim know that the state of the world depends upon Jews keeping Torah. So when Jews aren't keeping Torah and they try to be just like the goyim, the whole world suffers from it and it eventually leads to anti-semitism.
G-d thus made the rectification and elevation of all creation totally dependent on the Jews. To the extent that this can be expressed, we can thus say that He subjugated His Providence to them. Through their deeds, they can cause [His light] to shine forth and have influence, or, on the other hand, hold it back and conceal it.
The deeds of the other nations, on the other hand, do not add to or subtract from the state of creation, nor do they cause G-d to reveal Himself or withdraw. All they can do is bring about their own gain or loss, and strengthen or weaken their own directing angel. (Derech Hashem, Israel and the Nations, Ramchal)
Anti-semitism can only be fought by returning to Hashem and returning to Eretz Yisrael. Trying to fight it with hasbara is not only a waste of time but it is actually trying to fight Hashem rather than doing teshuva.