Most of the guards, the support personnel, all the people necessary to bring the Jews (and others) to the camps (capturing, transporting) did not have to kill anyone, but they were part of a system that is responsible for the death of +/- 7 million people. You just needed the killers to do the actual killing, but the industrialized process lowered the required number of people.

As for “local angry mobs to kill their fellow Jewish citizens”, do you have any source for it? I think it’s the first time I hear about it. Even so it would have been a limited number of people, compared to the number killed in the camps.