Assuming the Bible relates facts, there is a group of N historical people, of which one could plausibly say: "those N people had a hand in killing Jesus." I don't know how many N is. Maybe N is just 2 (Pilate and Caiaphas), probably more since we'd throw in the actual executioners who hammered the nails etc, other members of the Sanhedrin who voted, etc.
So some of those people were certainly Romans, some were certain Jews, some were probably Syrians working for Romans, some (like the members of the infamous crowd) may have been Hellenized Jews, Samaritans, some kind of Asians, etc etc etc. I don't know (or care) what the percentages are. But even if 99% of them were "Jews" (or the closest historical analogue anyway), that STILL wouldn't add up to the statement "The Jews killed Jesus".
Why is it so hard to distinguish the acts of INDIVIDUAL PEOPLE from the acts of their group?