Does this mean that whether this is

Does this mean that whether this is an act of procreation, an instance of friendship, or a house is a matter simply of individual perception or preference? Of course not. The fact is that things (institutions, relationships, actions, even buildings) can be man-made but nonetheless objective. There can be truth and falsehood even in artificially created or man-made phenomena.
Given these considerations, I shall argue that what morality is, what is meant by the word ‘morality’, is less in doubt, less contentious, than is generally recognized. It is indeed, in a sense, a human construct or man-made thing, no more simply ‘given in nature’ than marriage, friendship, football, or art. But the questions that really need our attention are precisely what it means to say that such disparate things as football, marriage, and art are human constructs, whether they are all man-made in the same sense or in the same way, whether, to what extent, and in what way they might also be said to be given in nature or natural, and what the implications are of acknowledging in each case that they are to this or that extent variously either human constructs or given in nature. After all, man cannot make anything: he cannot make square circles, he cannot double the number of degrees in a triangle, he cannot make something black and white all over. Conversely, he can build theories that are coherent or incoherent, clear or obscure, complete or incomplete, and that do or do not conflict with facts about the world (including other well-grounded beliefs). The fact that we recognize that in some sense we create morality ourselves does not mean that what we designate as moral becomes arbitrary. At the very least, we should be looking for a clear, complete, consistent, and coherent theory of morality that is compatible with our other knowledge and beliefs.
Take, for example, a library that needs to classify its books. Now there are hundreds of ways that a library might classify its books, including by colour, by height, by weight, by size, by length, by type of jacket design, by librarians’ preference, by subject matter, and so on. But only some of these approaches even begin to make sense in relation to the purpose of the library, which is to store books in a way that maximizes ease of retrieval or, more generally, use.
Given that people read books for their subject matter, we are immediately led to reject colour, size, and a librarian’s personal preferences, for example. Some form of genre categorization is called for because it is a fact (not an opinion or a preference) that fiction, biography, poetry, history, and essays can be distinguished. This is not to say that it was written in heaven that they must be, but nonetheless the distinctions are not arbitrary; they are given in the sense that we cannot wish them away or deny them, despite the true observation that they wouldn’t in some sense be there or have been formulated if there were no humans, and despite the fact that a particular group of humans might fail to make them. But the fact that some particular tribe does not distinguish between poetry and fiction (as in a sense the Homeric Greeks or Chaucerian England did not) doesn’t stop the distinction being there to be made. It may be conceded that one can argue about where biography ends and fiction begins, about whether this particular library needs or does not need a particular distinction to be utilized (perhaps the clientele here simply don’t mind what they are reading), about whether other categories are not equally or more important (sociology distinguished from history, perhaps; gay literature; ethnic literature). All this is true and takes a bit of time to say, so may look like a lot of objections. But there is no valid objection. The point is that given who we are and what a library is for, only a certain number (in fact relatively few) alternative systems make sense.