When 'christians' are asked to provide credible, tangible, vaild or verfiable evidence of their 'god'?

and instead subject the questioner to the most vile ad hominem attacks, are they just underlining their inability to engage in honest debate about the existence of their 'god'? Are they so short on facts and evidence that all they can do is screech about how bad a person must be to question the existence of their magical sky-daddy?