Meta - ethical nihilism does undoubtedly undermine the mores, values and norms of society as it claims that all life has no intrinsic value, and ergo acts that society considers abhorrent such as killing, are neither moral nor immoral. Of course this position is also logically flawed (according to moral realists) as ethical propositions describe objective features of the physical world.
Epistemic nihilism is also harmful to society as it holds that, truth is unattainable. This thus undermines all human knowledge that has been gained up untill this point.
Ultimately, Nilhism disregards objective meaning for human life, and allows subjective evaluation of what is "meaningful". This may not seem like such a problem now, but consider the idea of Creeping Normality. In, say, a hundred or a thousand years, conclusions that were once downright absurd might then be put on the table, and accepted as normal.
Thus, any intrusion of a philosophy which invalidates the worth of each and every human life, regardless of subjective fulfillment, is harmful to the advancement of society.
The Social Contract must protect the right to life, and Nilhism undermines this basis.
Put very briefly nihilism means life has no meaning that what we do on the broad scale of things doesn't really matter, however an individual can still live a fulfilling and to him and perhaps others a meaningful life which may benefit society, but in a billion years will it have made a difference.
They still have the instinct to survive and lead productive lives. You don't see any of them murdering others or committing suicide. They simply come to what they believe to be a logical conclusion, that everything is meaningless and exists for nothing. This belief doesn't change their entire mindset and is not pessimistic, it's simply a realistic view of things.
We don't believe that murder is justifiable and we don't just off ourselves. We believe life ultimately is meaningless but why harm others? They are just trying to find their meaning or meaninglessness. Nihilism is practically a view which might sound grim and harmful because it 'justifies murder' but in actuality it is just that life is meaningless and we accept that, in fact it's pretty awesome in some ways. For example, if we confirm that life is meaningless, you can pursue any interest as long as it doesn't harm others and if you fail then you shouldn't feel shame because life is meaningless. You are being bullied at school, but life is meaningless so this bullying is meaningless. Nothing can get in out 31st because life is meaningless.
For society to advance, we need to be willing to question everything. If we deemed some types of philosophies to be "Sacreligous" to society, society in itself would not advance. If we are truly able to advance as a society, we need to be able to question anything, and to question all moral principles is in itself a form of questioning.
Whatever harm nihilism causes, deeming it to be "Sacreligous" would be equally as harmful.
True nihilism can't be sacrilegious to the advancement to society, a true nihilist, once concluding that they are nihilistic, would stop doing anything, they would lay down and not move until they died of starvation or something. Anything less than that is not true nihilism.
The idea of nihilism isn't sacrilegious to the advancement to society because it's existence allows for people to think about it, thus causing their perspectives to grow, which is a good thing for society.