I don't see how claims of the divinity of Jesus factor into a determination of whether the person Jesus actually existed.
There is a distinct difference between evidence that the man Jesus existed and evidence that he was everything his followers believe him to be.
That he actually lived over 2,000 years ago is hardly proof that he is the Son of God, that he performed a few miracles, or even actually said any of the things the Bible attributes to him. I can imagine why, though, someone who not only doesn't believe in his divinity but doesn't want others to either,would find the contention that he did not exist, even as some poor schlub of a carpenter, appealing.
Since there are, obviously, no videos or photos of him walking about Jerusalem, and there isn't absolute consensus among scholars that he actually existed, the contention that he did not remains an option for the sane, but it's surprising that someone who finds near unanimity among experts on climate change to be all that's necessary to declare the matter settled and set the wheels of a massive response in motion, so stubbornly holds on to the small minority position concerning the existence of Jesus.