Even if two kids otherwise get exactly the same education and 'access to opportunities', the one with parents who do the thing is going to have an edge, all things considered. This logic works with any job. A child of a plumber is going to have an advantage in the plumbing world over a child of an accountant because they grow up hearing the language, picking up the tools when their parent isn't looking and then being taught to use the basic tools when they get s little older.

Personally, I don't see why society should be denied the extra skill that comes from that kind of informal home-education just to avoid 'nepotism'. Actual nepotism, where someone is given a job (or a place at a top university) just because of family ties… down with that!

In sum, I went a bit wider so you might disagree with me but I agree with you. Maybe 'nepotism' has class characteristics, which need to be considered. It might not even be a coherent concept in a later-stage of functioning socialism. If that's possible, the question is at what point in the development of socialism does nepotism become an incoherent concept? Then: has the DPRK or anywhere else reached it? If not, is it a problem?

in politics it is because of how politics works.