This to me regardless of whether or not Jesus lived there is incorrect logic. Well, up to now no city or hamlet has been uncovered that can be the Nazareth mentioned in the NT and during the first century so therefore it must not exist, etc.
There have been cities once denied by authorities of antiquity as being 'mythic' then later were discovered.
Instead of overtly denying this place existed during the proper time frame why not say up until now no such city has been found.
It seems it really is a bias against the historicity of Jesus and/or the proposed historicity of the NT that is the underlying cause of these assessments some being quite virulent.