Is it normal for parents to behave like immature morons in a situation

I know everyone says this about their parents, but this isn't just a "parents jst don't undahstand me!!1" post, this isn't about how they are in regards to me, it's about how they behave in a situation. I swear to god people's IQs go down when they get married, and then even further when they have kids.

Now my parents are (reasonably) intelligent people- my mother is one of the most intelligent people I know, but jesus christ. It's like every time the stupidest little thing happens they have to have a freaking argument about it, it's their natural reaction towards any situation and in the end it's not even an argument about the original thing, it's just immature snipes at each other stupid things like who works the hardest or who does the dishes or who's fault this other unrelated thing was. Who even freaking cares. The situation at hand usually has a seemly obvious solution, but do my parents sit down and talk it through logically like civilized adults? Do they hell. Apparently they would rather pointlessly argue about it until one of them storms out or marches around the house slamming doors. Grow the hell up.

And it's not even just my parents, they seem to get even worse if they divorce, especially if there are kids involved. My uncle just got divorced from a woman he had a kid with, and the whole thing has become less and less about their son and his welfare and more about their petty fights with each other and playing the blame game. It's idiotic and childish, if you have a kid yourself you should learn to grow the hell up and deal with things properly.

Now I never want to get married- I never did and my personal observations growing up around my family have put me right off- but if I ever did, I sure as hell wouldn't behave like that.