Some of them are out of touch. Richard Carrier (and those like him) distances himself from the crazy mythicism theories.
The situation is similar to the conspiracy theories. On the one hand, there are legitimate conspiracies (such as Operation Northwoods), on the other, there are some crazy ones (in my opinion), such as aliens in Area 51, big foot, etc… Pointing to the latter is often done in order to paint all conspiracy theories as nuts. It’s the same thing you are doing with the mythicists (I feel). Sure there are crazy mythicist theories, but Earl Doherty or Rich Carrier’s theories are not on the same level.
Look, even early Christians (such as Justin Martyr) claimed that Christianity was nothing new to them (and Justin was not a Mythicist!)
And when we say also that the Word, who is the first-birth of God, was produced without sexual union, and that He, Jesus Christ, our Teacher, was crucified and died, and rose again, and ascended into heaven, we propound nothing different from what you believe regarding those whom you esteem sons of Jupiter.
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And in that we say that He made whole the lame, the paralytic, and those born blind, we seem to say what is very similar to the deeds said to have been done by Æsculapius.
For having heard it proclaimed through the prophets that the Christ was to come, and that the ungodly among men were to be punished by fire, they put forward many to be called sons of Jupiter, under the impression that they would be able to produce in men the idea that the things which were said with regard to Christ were mere marvellous tales, like the things which were said by the poets. And these things were said both among the Greeks and among all nations where they [the demons] heard the prophets foretelling that Christ would specially be believed in; but that in hearing what was said by the prophets they did not accurately understand it, but imitated what was said of our Christ, like men who are in error, we will make plain.
So, According the Justin Martyr, there are similarities between what has bee attributed to Christ (by Christians) and to other deities by their followers, but, Justin explains this by claiming the devil knew all along what the prophesies foretold and copied them with the Greek deities. Ask yourselves. What is more likely? That Justin was right (and that the devils copied prophesies) or that Christ was a construct similar to that of other deities in that era?
And lastly, note that even in the Christian Scripture, there are bits warning Christians not to fellowship with people who deny that Christ has… come in the FLESH!
2 John 1:7 For many deceivers have gone out into the world, those who do not acknowledge Jesus Christ as coming in the flesh. This is the deceiver and the antichrist.
Bart Ehrman, a Jesus historicist, notes there were Docetists who believed Jesus did not have a human body/flesh, but only appeared to have it. I wonder what these thought about Jesus’ brothers and cousins! And which view was older? Docetic one or Jesus-of-the-Flesh one?
these issues/questions are not as black and white as Jesus Historicists allege.