i have been told that Antisemitism stemms soley from Religions, i doubt that.
I wonder what other people think how it comes into existance now adays.
The answer is that Antisemitism exists today because it was common in the past, and has a long history. I will explain.
Prejudices always existed. One can say being prejudiced is part of human nature, unfortunately. We are all prone to confirmation biases, which are crucial here. When you are prejudiced against a certain group you will tend to remember bad things that members of that group do more than their charitable actions. It gets even worse. You will also tend to assume that the intentions of said members of the group are bad, even when they are not. This is a self reinforcing mechanism.
The Jews were more unlucky than most, in that they were a minority under peoples which used hatred of Jews as a political tool. This probably starts with the Roman emperors of the Flavian dynasty which used their victory over the Jews to gain legitimacy. (They were the first emperors not from one of the big families - so they needed that.) Then there was the small issue of Christianity becoming the dominant religion in Rome, and the need to deflect the fact that the Roman's were the ones which killed Jesus.
Following this there was very long period where Jews lived under the rule of people who hated them. Since Jews were forbidden to own land, they were pushed to jobs which were forbidden to Christians, such as lending money. You can imagine that many Christians felt it was humiliating to be in debt to a Jew, increasing the level of hatred. All these factors reinforced each other.
In some part of the world the religious part is gone, but the underlying confirmation biases, and the tendency to interpret intentions are still there. Just look at the Helen Thomas or stone throwing incident threads. I identify a tendency to dismiss claims by Jews of antisemitic incidents without considering the details of said incidents. Alternatively, in some cases people admit that said incident was racist but try to explain and contextualise it. The same people would never dream of doing the same for an anti African-American act made by the KKK. This is really disheartening.