Bart Ehrman doesn’t even believe Jesus rose from the dead. Why does citing him help the case for anything here?

Ehrman is cited here for one narrow, specific fact: that Jesus was crucified under Pontius Pilate, not for the resurrection. He’s an agnostic historian with every incentive to be skeptical of the Christian story, and no reason to concede a point that helps the case for Christianity unless the evidence genuinely requires it.

That’s exactly what makes the citation strong rather than weak. When a scholar who rejects your conclusion still grants one of your premises, that premise is about as solid as ancient history gets, which is why his agreement here, alongside similarly skeptical scholars like Gerd Lüdemann and John Dominic Crossan, carries real weight.