The Historia Augusta is an astonishing piece of bogus history. It is perhaps showing us a Roman sense of humour, but I think scholars are generally unaware of why it was done. There are 130 fake documents and they even invent sources that disagree with them. Sounds a bit like Christianity to me. The Flavians destroyed Jerusalem and then Christianity appears. All reliable sources from this time come from Roman hierarchy. Tacitus, Suetonius, Pliny and Flavius Josephus all support the existence of early christians, persecutions and Jesus. Ever wondered why Emperor Constantine has the name Flavius? The first to do so since Emperor Domitian. The idea was to create a religion that would unify the Empire under one God. That is why Christianity spread so fast, it had the power of Rome behind it. These highly educated individuals created many characters, as authors and in "life", they also altered other writings and generally tried to make things as confusing as possible. The only way you could write anything without it getting into Roman hands, was to put it in clay pots and hide it in caves. Using the methods applied to the Historia Augusta, it seems all writers are linked to the Flavians and members of the Piso family. What is your view of this explanation? I could, of course, elaborate on every aspect of the topic, but thought i would give you a summary of this explanation. Perhaps you have heard it before, perhaps not. And yes, that means that all of the Roman sources are lying, a quick look at the Historia Augusta should confirm what they are capable of.
This theory is interesting. I think you might want to consider the possibility that you are guilty here of taking too much from a single document and the implications of that document. The Roman world was not monolithic and there were many voices. I am not saying that your points are irrelevant, but just that the real story is broader and more complex than your simplification. It is true that much of history has been so biased that it virtually amounts to pure lies and propaganda. Perhaps the Historia Augusta deserves such a label. However, to include Tacitus, Seutonius and Josephus with a broad stroke and imply that they were all a bunch of completely unreliable liars is simply not fair. Each author should be taken one at a time on his or her own merits. I believe your view of Constantine is fairly accurate and your view of his effect on Christianity is not the whole story, by far, but that there is some truth in this idea as well. I do believe you ought to temper your cynicism specifically with regard to Suetonius, Tacitus, Pliny and Josephus. All had their biases, but the consensus of historians is that the work of all four of these men is not without merit and that it is vastly superior (despite the limitations) to the Historia Augusta. We should apply the Golden Rule (treat others as we would want to be treated) even with regard to pagan historians of the past.