It was a joke invented by the jews themselves.
Who would have thought that they would have created their own jokable problem.
It was the fact that a non-jewish person thought the joke was for real.
Thats when it spread.
And then everyone began to believe that all jews have big noses.
That is why its best not to assume everything is true from what others say.

I ask questions but only as I philisophically speak to myself.
It is then that I will share the outcome that the question held in itself, to the world.