- Why did everyone start to hate the Russians if the U.S. did the same thing in Afghanistan, Iraq?
- What needs to be corrected in the management of Russia first?
- Why did Blaise Pascal become a religious man at the end of his life?
- How do I know if a guy likes you?
- When they say "one generation", how many do they mean?
For the same reason that you don't notice that your computer is buzzing or that you have a huge nose in the center of your field of vision. Over time, you get used to any kind of stimuli, so you stop paying attention.
And chomping is even closer to a pleasant routine, rather than something completely out of the ordinary.
PS I don't slurp myself, just because I get mad myself when I hear others and I feel sorry for the ears of all the people around me.
They don't notice it because they don't want to notice it, they're used to it, it's normal for them. But there are no secrets in the physiology or brain, it's all about education.