I genuinely believe that these people see "the Jews" and "Jewish people" as two entirely separate concepts in their head. One is the group of people they may know, hang out with, be friends with, and one is the concept of evil brought up by conspiracy nuts that get associated with murdering babies and widespread paedophilia.
I've read an article, linked here during the Trump administration, about people of Mexican origin being deported from American towns. The townsfolk were upset that their friend or neighbour was being deported, but they still believed in Trump's promises. They didn't want this to happen, they only wanted "the bad ones" to get out, whatever abstract concept of "the bad ones" meant to them. The people they knew were always "one of the good ones".
Obviously, no group of people is uniform, but the human brain loves to think in groups. The groups can overlap and they don't need to make sense; they exist purely to attach some kind of judgement or prejudice onto. Probably a great feature of the human brain if you're a primate trying to make it to adulthood, but, in modern times, humanity's worst flaw.