I thought passive filter should exhibit more worst case response than active filter. Is there any reason while the nominal response is closer to the worst case response(red).
No, in contrary! Several years ago it was prooved by Orchard that the tolerance influence is minimal for a passive ladder structure (doubly terminated). These good properties are preserved also in case this ladder structure is realized by active elements (active inductor realization or FDNR technique).
Ref.: Orchard HJ: Inductorless filters, Electronics Letters, 1966 (vol 2), 224-225