I don't think its a black or white thing. There are stained relationships which still maintain civil and they are ones that are totally unhinged. 
There are also scenarios where it get unhinged when the parents are actually seperated and put the anger on the child. 
Its a situation where you should look individually at it. But I agree, that there should not put blame or burden on a child. Parents have to fill a role and put their individual needs behind. But there are so many factors which can influence the situation.