Dear scholar JW,
This is what he claims (among other things) does not exist in order for his arguments to work:
It is called the Alexamenos Graffito, and it hangs in the Palatine Museum in Rome. It is from the late 1st or early 2nd century. Etched on a slab, it was made by Romans making fun of a Christian. It states, in Greek:
"Alexamenos worships [his] God."
It is, of course, the etching of a man, worshiping a crucified person, with the crucified person being insulted by given the head of a donkey.
The cross is, of course, the shape of the type testified to by Josephus, Lucias, and secular writers were are also asked in this work to ignore (I am sure you remember because you write as though you have read this work).
Such an act has a name, to "suspend belief," and means to ignore facts or the truth in order to momentarily believe in something, like a work of fiction or a fairy tale.
So say and believe what you want. I am not bothered one bit by your views. Your views are not facts, nor do they change realities.