Almost everyone say that hate social engineering. Many people hate social engineering with a passion, and for good reason. Most people's gut reaction to social engineering is that it is unfair and tricky, somewhat like rigging an election. For moral libertarians, who believe in the equality of liberty (and hence moral agency), social engineering is unconditionally unacceptable, because it means that those doing the engineering are making important decisions, often moral decisions, for the subjects of the engineering. Wherever there is social engineering, there is no respect for the principle of equal moral agency, and hence no respect for the equality between humans. From a moral libertarian perspective, social engineering is simply immoral.
Another thing about social engineering is that it is much easier to oppose social engineering designed to achieve outcomes you don't like. For example, conservatives are good at spotting the slightest leftist slant in public education curricula. But the same people would often justify pro-conservative social engineering, such as government policy that favours heterosexual relationships over homosexual relationships, as either upholding tradition or upholding the will of the 'silent majority'. This is actually a double standard, because social engineering is still social engineering, even if it has been carried out for hundreds of years, and even if it is supported by the majority. From a moral libertarian perspective, the principle of equal moral agency is still violated, because the individuals making decisions in government are still making moral decisions that all other individuals in society must accept, even if against their own will. The government is still the moral master, and the people are still the moral slaves. In fact, if those supporting conservative viewpoints truly believe that they have the unwavering support of the majority, they really do not need the government to uphold anything. If they allow the government to step aside from governing the moral sphere, private individuals will regain their fair and equal share of moral conscience, and conservative individuals (which conservative politicians believe are the majority) will be able to live out their conservative beliefs by personal example, much more effectively than when government interference exists.
The left is similarly blind when social engineering favours their worldview. While the left is generally unsympathetic to social engineering for the sake of preserving the status quo, they are much more sympathetic to social engineering that will supposedly promote equality of outcome. In many leftist circles, free speech is becoming increasingly rare, and policed speech is increasingly becoming the norm. So-called safe speech is often justified on the need to protect the feelings of minorities, but in reality it is a form of censorship, that effectively disallows certain ideas from entering the free market of ideas (or John Stuart Mill's cauldron of ideas if you prefer that analogy). Even if you start with, for example, the seemingly clear-cut rules of only prohibiting racist and homophobic speech, it effectively sets a precedent that can potentially disallow political speech promoting pro-life ideas (because it hurts the feelings of women who had abortions) or cultural expressions that are deemed to be cultural appropriation (because it hurts the feelings of people who don't wish to see cultural appropriation). And once it becomes acceptable to ban political speech and cultural expressions, there really is no limit to what else can be banned. A Stalinist dictatorship is the only logical conclusion.
Another worrying recent development is the prioritization of people's right to speak, based on their personal characteristics. This was first seen in the 'progressive stack' speaking system that was used in some Occupy rallies, where women and minorities were afforded priority in their right to speak. This system clearly sees people as members of groups rather than individuals, in a way not unsimilar to how old-school socialism saw people as solely members of their economic class, or how fascism saw people as solely members of their nation and their race. In the name of achieving some sort of group-based equality, the principle of equal moral agency between individuals is sacrificed. Furthermore, as the progressive stack is a social construct invented and maintained by leaders of leftist movements, it is a system in which they decide the rules, it is therefore by definition a system in which the leaders have much more moral agency than anyone else. From my personal experience, it is not uncommon for those who have the right to decide who is to speak to use their power to favour those who will say what they want to hear. In recent years, I have heard from an increasing number of women and LGBT people complaining that they have been excluded from systems and institutions that are supposed to be inclusive, because those running the system don't like to hear what they have to say. (Those running the system often like to counter that people who promote 'regressive' ideas are to be excluded. However, this definition of 'regressive' is a subjective one, and often bears no relationship to the more objective definition of regressive I use, i.e. does not bring any new value to anyone beyond what has already been offered. In fact, I often suggest that, if an idea really meets the aforementioned objective definition of regressive, it will be rejected in the free market of ideas, so we don't need to do anything about it.)
p.s. A particularly worrying feature of leftist social engineering is that it is often inspired by theories arising from sources like philosophy, sociology or feminism. While I believe it is important for people to critically reflect on the state of our society, and many such theories have given us useful language and frameworks to discuss important issues, the theories themselves are almost always far from flawless, to put it mildly. In fact, I make this observation about history: although progressives have been the winners throughout history (because, by definition, only new ideas can change the course of history, restating old ones cannot), progressives of any era only get a minority of things right, and more progressive ideas eventually get rejected than accepted. The French revolution's Liberty, Equality, Fraternity lived on, but their revolutionary calendar did not. Similarly, 19th century socialists played a very important role in highlighting the injustices of early capitalism towards the working class, but their demands to nationalize industries have been largely rejected. Karl Marx's prediction of the collapse of capitalism has not come true either. This is not to say that the investigation of society and the production of progressive ideas is not worthy. It just highlights the need for such ideas to be tested and refined in the free market of ideas.