Because Jesus is so important to Catholics.
And He is just as important to Protestants. That doesn’t answer my question in the least.
Jesus is important because He is Jesus, not because of anything His earthly parents did or didn’t do.
This is similar to the question of the Pope Infallibility:
Do you believe it?
Well, the question should be: “Do you believe in God?”
If the answer is yes, then there should be no doubt all the other minor miracles are also possible.