El Grecko, I think you are vastly overstating the case. I have been going to both countries since '74, I have been married to a Flemish Belgian since '76.
It's true that there is some tension in Antwerp however this is in large part due to the fact that it (Antwerp) gets invaded each weekend by many Dutch young people who are rather noisy and boisterous, not to say a little arrogant. One thing it does show is that the Dutch know a wonderful city when they see one.
Whatever tensions do exist they pale into nothing when compared with the Flemish / Waloon divide though even this has become more civilised in recent years.
I speak fluent Dutch, have many Dutch and Belgian friends, I just don't recognise the picture you paint.