All types of identity "studies," while needed to remedy some neglected areas of academic inquiry, focus on just one part of a person's identity.
Intersectionality is an acknowledgment that a couple of identities make you up. But we're even more complex than that--we are individuals who act and love in particular ways. None of us can fit neatly in any identity category.
Arendt's pariah offers a two-fold critique: On the one hand, of politics, from a particular perspective. On the other hand, of identity categories themselves, which always also need to be critiqued. Particularity is so important to Arendt that she could never get on board with an identity category that wants to overpower particularity.
This is relevant to unexpected Trump voters, pro-life women who participated in the anti-Trump march, etc.