This is really not the issue. It's not that it's just "stuff no one believes anymore but they used to."
And the idea that just reading the Bible tells anyone what the content of Christian belief is - that's simply not true and has never been true.
Dawkins makes arguments about the very basics of Christian theology that really misunderstand what they mean.
Before anyone can make a solid attempt at criticism of any argument, they need to actually understand what it is supposed to be saying. Whether it's in theology, the sciences, or anything else.
He makes basic errors around epistemology as well, not just Christian epistemology. Many of his arguments are based around the idea of how we know what is true, which is a huge and foundational part of philosophy. It's clear he doesn't know even the most basic elements in this area.
The historicity of Jesus is just an embarrassing addition to it all. You could not go into any university department teaching ancient history and make the claim that Jesus was not a real historical person without some pretty amazing new evidence or thinking - you could certainly never get a job. The mistakes people make about this, including in this thread, again show that they just don't understand the standards for historical evidence in the discipline, and how they work.
Of course Dawkins, or anyone else, can have any opinion they like, and he doesn't "need" to engage with anyone. But if anyone is going to write a book on a topic and claim it's making a solid argument, and really be quite disparaging of anyone who disagrees, and yet openly admits they don't know anything about the basic elements of the subject, nor do they know the basic background or methods in the areas of knowledge they are discussing, it should be no wonder if people don't take them seriously and think they are being pompous fools.
The other discussion people are having on this thread arou about those infamous articles in Nature and SA - where they are saying, the authors clearly didn't know anything much about DSDs, they make basic errors about human biology, they conflate things that are not related in the way they think - that is, they don't know what they are talking about and look like idiots as a result.
It's not even like it's just theology he gets wrong. He has problems with his knowledge and understanding of historical study and philosophy.