The postmodernists think that they are achieving freedom by liberating people from grand narratives. What they do not appear to understand is that there are all sorts of ways in which people can imprison themselves and others that do not involve grand narratives.

Imprisonment can happen in families; in communities; in religious groups. It can happen in business and government. It can happen in mafia and the gangs. In most of these cases there is no grand narrative being taught. There are simply abuses of power and attempts at controlling people. In all these cases, once again, it has nothing to do with grand narratives, and doing away with grand narratives does nothing to correct the problem.

So we have beliefs such as that there is no absolute truth and even that truth itself is relative. This is completely wrong. There is nothing relative about the Sun. Truth is complex; reality is complex; and there is more to both than what many people would like to believe. That does not mean that either truth or reality are relative.

I have education in science; I also have had extensive dealings in such things as astrology, meditation and Christian religion. These tell different stories. All have a part of the truth. In all cases the knowledge is absolute. We are dealing with different aspects of reality; it does not mean that these are relative or that there are no absolute truths.

Where postmodernism becomes helpful is in getting people to look at things that haven’t been a part of their education. A person reared in Christian fundamentalism would think that anything that is not in the Bible is of the Satan, and the idea that there are no absolute truths can help him to pay attention to things of wisdom that have not been a part of his upbringing, such as what we see in science and in non-Christian spiritual paths. In educational settings this is an advantage, which is probably why this idea has become so influential in the academia. However in the adult world this idea is ruinous. It leads to unethical conduct. You may want the belief that there are no universal truths in a student. You do not want the belief that there are no absolute truths being practiced by a doctor or an engineer, who have to be absolutely certain that they are dealing in reality and for whom the belief in no absolute truths means murdering their patient or designing equipment that will blow up on use.

Have there been people imprisoned through grand narratives such as Communism, progress and Islam? Yes there have been. However many more have been imprisoned without the aid of grand narratives. The tendency for people to enslave other people has existed for as long as there have been people, and I expect it to continue existing for as long as there are people.
In claiming to end the tyranny of grand narratives, the postmodernists have created their own grand narrative. And that has lead to many undesirable results.