The citizen doesn't seem to be against Sulla. In fact they disallow Marius from coming in.
Its citizens were offered Roman citizenship in 90 BC in the Social War, when concessions had to be made by Rome to cement necessary alliances. In Sulla's second civil war, Gaius Marius the Younger was blockaded in the town by the forces of Sulla (82 BC). When the city was captured, Marius slew himself, the male inhabitants were massacred in cold blood, and a military colony was settled on part of its territory. From an inscription it appears that Sulla delegated the foundation of the new colony to Marcus Terentius Varro Lucullus, who was consul in 73 BC. Within a decade the lands of the colonia had been assembled by a few large landowners.