It is, I guess, as unproveable as ‘everyone agrees.’
But since, it is alleged, that Israel stole enriched uranium from the US Navy, it doesn’t sound like the US was supplying them.
I assume “stole” is a euphemism for “they were tipped off about an opportunity, guards were oddly absent at critical moments, and the ‘victim’ showed a remarkable disinterest in investigating the ‘crime’.”