That is because up to now the Indian vote has been large enough to guarantee them victory.
But now that they have lost control of the parliament, the Indian vote continues to shrink, and the black/mixed vote remains hostile rigging is a distinct possibility. The PPP feels that they have a god given right to have power, and will not accept defeat!
The point here is we are seeing the adverse effect of dependencies on racial demographics rather than good sense, good management style and in general good government.
The PNC will inevitably do exactly what the PPP is doing. That they will has nothing to do with racism or genetic disposition but it is what anyone would do given the kinds of electoral dictatorship our system produces.
The only mediating force is the AFC and the next elections will make them even more indispensable as people see their emerging role as the final arbiter. Theirs is a large responsibility to which they must be prepared to respond.