With the exception of the pariah folk themselves, the actually ostracized and downtrodden of the world could find comfort in Malacath I would assume.
My only issue is, by comfort, that usually means vengeance. Malacath is the outrage of injustice, and not the compassionate care of say Mara.
Malacath is for the people who have been wronged or faced with injustice and cannot let it go, the reason Malacath may appeal is because in many cases the anger and need for retribution could be justified.
Malacath certainly appeals to me, personally, I've always been drawn to ostracized characters and characters who are "friend to the friendless" types but Malacath is not your friend, Malacath is the voice in your head telling you that justice is only served when someones head is by their feet. Malacath is the fury detonating within the soul of a someone pushed beyond their limits by deciet and betrayal. Malacath is the voice in someones head saying "You're not dying now, your enemies need to die. Get. Up."
He's the driving force behind brutal, bloody justice and the one who cares when you are wronged.