Like you, I am agnostic... I've been in too many foxholes and seen too much shit to be an atheist... but, in regard to your question... the originator (let's say Jesus if he returned) would be fried and served up to the masses on Social Media and would be hailed by the very population that supposedly 'follows Him' as being a liar and a heretic, discredited and declared a 'false prophet'...What I wondered was if the originator of a religion like Christianity or Buddhism would come back/be reborn after a few millennia and preach his original message, could it be that the faith he started could have deviated so much from his original teachings that they would consider him the anti-christ?
...He could be sitting in a pew of a church that supposedly worships Him and they would cast Him out for being disheveled and too poor looking to treat with any respect by the very patrons of that church.