Two different animals. Pathology of certain underclass groups consists in a social order or everyday life interaction that is pathological by broader standards- such as the promotion of behavior (such as violence) that is valued by the subgroup in question but not valued everyone else. The fascist-orchestarted scapegoating, otoh, is breaking the everyday social order that most people subscribe to and engaging in a behavior that these people would consider pathological under most other ciccumstances.
Stated differently, a member of a pathological sub-group engages in a violent act because this is consistent with the norms of his group and that behavior will earn him peer respect. However, when a member of "respectable" social group engages in a pogrom, his behavior violates the norms of his community and he knows that, but he does it anyway - perhaps as an expression of a power trip or other sort of perverted gratification.
I've seen a lots of seemingly "normal" males deriving a perverted sense of gratification from putting down or assaulting people who cannot defend themselves (their wives, girlfriends, children, nerds, even animals) - and something very similar is at work here. There are two distinct aspects of this type of behavior - its quasi-justification (e.g. she asked for it, she pissed me off, they are responsible for our plight, etc.), and and the gratification form exrecising direct power and control over someone else (physical violence, killing).
Wojtek