I bet most of you would end up appearing dumb if you were on the show. Its very easy to judge someone as smart or dumb while watching the show unfold on television where the machinations and manipulations of each and every participant are laid out threadbare for us to see. Its lot more difficult to be inside the house and judge the situation when you don't know whom to trust and where people keep changing their loyalties and strategies every day.
Shonali may be naive and too trusting, but that doesn't make her a dumb person. Being too emotional and straight-forward, she doesn't either play politics or use any strategy to strengthen her position and outwit others. At the most, I would say she is a bit dumb for this show...or rather not sufficiently prepared for this show.