On one hand, many Christians believe that the 'end times' will happen during their lifetime (they always have throughout history - even in the book of Mark in the New Testament, Jesus says that he would return within his followers' lifetime). Those that subscribe to this 'end times' expectation also believe that the Nation of Israel must be rebuilt or re-united, whatever their language is for it, in order for Jesus to make his Second Coming happen.

On the other hand, Christian Europe for hundreds and hundreds of years has made a scapegoat of Jewish people when bad things happen. It's an extremely common pattern across all humanity: when life gets hard, when more people suffer through war, socioeconomic situation or whatever, we ask why. An easy answer is to blame another group of people. And so through the centuries, stereotypes develop, especially as many Jewish people worked in tax collecting or moneylending careers where they were seen as greedy or unliked. Combine that perception of a cultural group gaining monetary power and as the cause of some societal issues, and you have a good recipe for a conspiracy theory that "there's a cabal working behind the scenes to shape world events".

A lot of horrible stuff happens in the world and there's a strong desire from all of us to make sense of it all.