Of course it is. Science, generally, is a social construct. Everything that human beings do and “know” is a social construct, in that human behavior and “knowledge” are products of acculturation and the irrepressible urge to name and classify things.
Whence that urge? You might say that it’s genetically based. But our genetic inheritance is inextricably twined with social constructs — preferences for, say, muscular men and curvaceous women, and so on. What we are depends not only on our genes but also on the learned preferences that shape the gene pool. There’s no way to sort them out, despite claims (from the left) that human beings are blank slates and claims (from loony libertarians) that genes count for everything.
All of that, however true it may be (and I believe it to be true), is a recipe for solipsism, nay, for Humean chaos. The only way out of this morass, as I see it, is to admit that human beings (or most of them) possess a life-urge that requires them to make distinctions: friend vs. enemy, workable from non-workable ways of building things, etc.
Race is among those useful distinctions for reasons that will be obvious to anyone who has actually observed the behaviors of groups that can be sorted along racial lines instead of condescending to “tolerate” or “celebrate” differences (a luxury that is easily indulged in the safety of ivory towers and gated communities). Those lines may be somewhat arbitrary, for, as many have noted there are more genetic differences within a racial classification than between racial classifications. Which is a fatuous observation, in that there are more genetic differences among, say, the apes than there are between what are called apes and what are called human beings.
In other words, the usual “scientific” objection to the concept of race is based on a false premise, namely, that all genetic differences are equal. If one believes that, one should be just as willing to live among apes as among human beings. But human beings do not choose to live among apes (though a few human beings do choose to observe them at close quarters). Similarly, human beings — for the most part — do not choose to live among people from whom they are racially distinct, and therefore (usually) socially distinct.
Why? Because under the skin we are not all alike. Under the skin there are social (cultural) differences that are causally correlated with genetic differences.
Race may be a social construct, but — like engineering — it is a useful one.