Just vs. unjust is what captures the social construct part. How do you decide what is just vs. unjust? You either poll society as whole, the elites of the society, or the monarchy, depending on the type of government.
The entire field of moral philosophy is dedicated to this question. There are many ideas of how to characterize justice. I can't tell you what idea of justice you should subscribe to. There are tons of texts doing that much better.
Im just pointing out that the argument that something is bad because it is discrimination is circular. Unless you also argue why that particular form of discrimination is unjust (in whatever sense you prefer).
Morality is subjective at its core, so you can't "argue" that something is unjust, and the fact that moral philosophers baselessly think they can doesn't change this fact.
The entire field of moral philosophy is dedicated to this question. There are many ideas of how to characterize justice. I can't tell you what idea of justice you should subscribe to. There are tons of texts doing that much better.
Im just pointing out that the argument that something is bad because it is discrimination is circular. Unless you also argue why that particular form of discrimination is unjust (in whatever sense you prefer).