I think Lemmy has a problem with history in general, since most people on here have degrees/training in STEM. I see a lot of inaccurate “pop history” shared on here, and a lack of understanding of historiography/how historians analyze primary sources.
The rejection of Jesus’s historicity seems to be accepting C S Lewis’s argument - that if he existed, he was a “lunatic, liar, or lord,” instead of realizing that there was nothing unusual about a messianic Jewish troublemaker in Judea during the early Roman Empire.
Secular sources for his existence aren’t exactly abundant, but they’re fairly convincing. Certainly there are historical figures from that long ago with less evidence for their existence