If Jesus died on a stake, then how do Jehovah's Witnesses account for this?

Alexamenos graffito, an inscription carved in plaster on a wall near the Palatine Hill in Rome, among the earliest known pictorial representations of the Crucifixion of Jesus, late 1st to the late 3rd century. It depicts a human-like figure affixed to a cross, has the head of a donkey, clearly he's being mocked. One other figure, just human, below is seen offering some action to this donkey headed victim on a CROSS.

Carved also is a crude Greek:

Αλεξαμενος ϲεβετε θεον ϲεβετε,

meaning

"Alexamenos worships [his] God."

Oh sure, Jehovah's Witnesses can go on about how "Stauros" (σταυρός) actually means "stake" not "cross" even though the majority of real scholars disagree. They can erroneously claim that Romans highjacked Christianity, adopting "the pagan symbol of the cross." Out of all the disputes over whether Jesus died on an upright pole or cross, however, how do the Jehovah's Witnesses account for the mockery of Jesus on the CROSS being worshiped as God by an early Christian (who is also the subject of ridicule), if the Romans between the 1st to the late 3rd century, who would have known how crucifixion was done, put Jesus on a stake?