I think you spent some time writing this reply so I'll make a reasonable effort to answer your questions. But I'm guessing you're a bit more committed in this issue than I am. So please don't be disappointed if I won't get into a long point-by-point argument. And please note that I've actually said nothing about Jesus so far.

And we have contemporary writings for everything single figure we believe to be real in ancient history?

I'm quite certain we do not. Non-contemporary sources can do just fine, and then there are artifacts of course.

Most of the writings we have of historical figures are posthumous.

That sounds very reasonable.

Not having contemporary writing for someone in the ancient world is not a proof that they didn't exist.

I agree.

Your claim is no more than a non sequitur.

There's no non sequitur without a conclusion. I was just pointing out a couple of obvious things about what you cited from Tacitus.

Do you really think that poor disenfranchised Jewish revolutionaries would be able to write who followed Jesus, an obscure disciple of John the Baptist by most accounts. If I'm not mistaken the amount of people able to read in the ancient world would of been something something like 10% at best and the amount that could write would of been far less. Out of those who could write how many of them would of been capable of writing a book?

I think it's safe to say that even the ancient Christians have proven capable of putting a thing or two down in writing.

Ever read up on Josephus?

I think I've had a quick glance on Wikipedia when he was mentioned in a similar discussion before. So, no, I can't say I've read up on him.

There is a reason why he was so successful at infiltrating the ranks of the Roman elite. Someone who could write a book in the ancient world was a very valuable assets.

If you say so.

You have to come up with an alternate explanation for the rise of the Nazerians and Pauline Christianity if you want to say that Jesus didn't exist.

I'm not sure I want to say that. Also, I'd have to read up on the Nazerians and Pauline Christianity before I could explain them in any way at all.

What explanation do you have that it is all an elaborate conspiracy?

Now you're giving me an either-or fallacy. I've claimed no conspiracy.

I think occam's razor rules that one out.

But a conspiracy is not the only alternative to a historical Jesus.

Also who is going to care enough about a Jewish criminal who at most only attacked money changers in the temple if that account is even reliable? I doubt any contemporary Roman sources had any reason to write about Jesus during his lifetime.

I'm not sure I follow. Are you asking "If we disregard all the Gospel stories about Jesus, what reason was there to write about him"?

He was a very obscure figure and only seemed to come to the attention of the Romans at the very end of his career were they executed him for claiming to be a king without authorization from the Roman senate?

At least he supposedly was conspicuous enough to be the victim of an elaborate conspiracy.

So I've provided you with evidence and you've moved the goal post not understanding how historians evaluate ancient historical claims and text, what evidence do you have to the contrary?

I'm not offering any evidence. I'm offering my opinion on evidence on the historical Jesus. My opinion that you're replying to is that the actual Christians themselves that Nero persecuted and that Tacitus writes about are way better evidence than that single line where Tacitus mentions Christus.

Do you want me to prove to you that I'm not just a brain a Jar?

If it's not a terrible inconvenience for you to do so...

Your not going to be able to say anything with absolute certainty about Ancient History it's not the same as modern history and we do not use the same methods. At most we can only say what probably happened and as it turns out using the historical critical method we can say that Jesus probably existed. There is far more evidence that he did exist than evidence for him not existing and we have more writings about him than we do for other ancient figures like Socrates.

It's curious that you should pick Socrates as an example. Are you familiar with the Socratic Problem? Now I've only taken an introductory History of Ideas course, but it was explicitly stated that as we only know Socrates through the writings of others he might very well be entirely fictional, but it's really only the fictional Socrates that matters anyway, as it's the only Socrates we know.

To me, it's the same with Jesus. It's the Jesus of the Gospels that matter. What difference does it make if the stories were first told about an actual person or not?

We know that Paul, the author of Mark and the Author of the Coptic book of Thomas are all drawing upon an older source for their Jesus material, so we know that the Jesus tradition predates them and non of them simply invented Jesus ex nihlo. How do you explain this tradition?

I don't think I have to explain them at all. I'm sure an historical Jesus is not the only possible explanation though.

Jesus was a suffering messiah an idea that is unheard of in Jewish lore about the coming savior. What Jew would believe that a savior would come in defeat and not triumph? All the Messianic prophecies in the Tanak have the coming savior arriving in triumph and defeating the enemies of God. None of them say that the Messiah will be crucified and humiliated.

Myths and stories change and merge all the time. And sometimes they even are created out of thin air.