If something is a taboo, it is considered morally reprehensible to the overarching society. It is not discussed, it is not done, it is a big bad no no.
Political Correctness is not that extreme. It is more of a folkway than a taboo. Folkways are things that are frowned upon in "proper" society but that still may happen.
Again I will use my example. Sleeping with a dead person = taboo. Speaking ill of them = folkway.
Or maybe lets think of something that is more in line with PC.
It is not PC to insist that only boys can play football. It is taboo to beat girls who try and play football.
As a former educator and a mother of boys I can tell you that this is not a reality. Boys (especially minority boys) falling behind in primary education is a major issue that is impacting education reforms. But like
@slant said, I don't think this is a PC issue.