It isn't natural, it's part of the culture.
The worst I've seen was so bad that when I refused to interrupt, I waited 45 minutes without an opportunity to speak and then the meeting was over. Literally a 45-minute chain of people interrupting each other. That's not natural, that's adapted behavior.
Fortunately, it's a rarity at my current place of work :)
All it takes is a few bad apples and everyone else will adapt and interrupt as well.