1) Bokononisn is a placebo religion which extols the virtues of placebos.
2) Small quantities of nihilism can have a positive effect, as solvents acting on rigid and wrong certainties. But there is a part of us which is continually planting new seeds, and if one is compelled to stamp those out too, then it has become what it replaced. I suppose the nihilism of nihilism is belief.
I am not as far gone as Vonnegut, but I think we share (you know he is out there somewhere) a profound love of absurdity.