Because its an unfalsifiable hypothesis, you cannot disprove them and you don't need to either. The disbelievers do not bear the burden of proof. The burden of proof is on people who claim to know what resides in reality. It falls in the category of any other unfalsifiable hypothesis like dragons and fairies. Even if there's proof of Jesus its not proof that he was the son of god or any other supernatural claims. But you're not willing to budge because you've heard all of this before and you refuse it even though its irrefutable.