We all look at evidence through the lens of theories and other frames of reference. Sometimes sufficient evidence accumulates that does not fit with a theory, with the result that it is abandoned and a different theory is adopted, one that better accounts for the evidence (or for more of the evidence). In the mean time, when there are only a few such pieces of problematic evidence, there is nothing inappropriate about seeing whether it is possible to reinterpret the evidence so as to fit the theory, rather than vice versa.
In the case of mythicism, the amount of data that needs to be explained away or reinterpreted is not insignificant. One has to suggest alternative meanings for Paul’s phrase “descended from David according to the flesh.” One has to relocate the crucifixion from the place where crucifixions were a regular part of people’s lives. Many other examples have been discussed on this blog in recent days. Some are very problematic to fit with mythicism, some are less so, and some not at all.
At some point, unless one is dealing with “true believers,” it becomes appropriate to say “I want, to the greatest extent possible, to have a theory that fits the evidence, rather than vice versa.”
The view that there was a historical Jesus accounts for the data I’ve mentioned (and the other similar examples) better than mythicism. But what makes it so compelling to scholars is that it also can account for all the material that clearly or probably was invented later. In short, with the approach of mainstream historical scholarship, you get all the benefits that mythicism offers (such as they are) but without the serious defects.
I think this is my #1 reason for not being a mythicist. I consider it appropriate to create and/or adopt a theory that fits the evidence, rather than vice versa, whenever possible and to the greatest extent possible. This is also, I suspect, the #1 reason that I’ve compared mythicism and creationism. It is not that history and the natural sciences function in precisely the same way or offer comparable levels of certainty. They don’t. But in the case of both mythicism and creationism (both of which have many permutations and varieties) I see a deliberate attempt to reinterpret evidence to fit an already-adopted theory, when that evidence can be explained in a straightforward and persuasive matter by another theory.