Math professors are always telling their students that math is useful outside of the classroom and is needed in many aspects of normal life.
Then the students go home and see that their stupid parents don't know algebra or trigonometry or much of anything beyond basic arithmetic, yet manage to get through life all right.
So the student correctly assumes they don't need math. They also assume math is useless in ordinary life.
You know how a few years ago Wal*Mart started posting cost per ounce beside the price of food items? Useful! Now you can easily compare different-sized items. I, however, learned from my dad years and years ago to do that myself. It requires division.
This is why your math professor says he uses math in daily life and your parents say they don't. Your parents went without the cost per ounce information before Wal*Mart gave it to them pre-calculated and it never even occurred to them to calculate it themselves. The math professor saw the opportunity to use math, and so he saved money. There are also many cases where more advanced math is useful, but not required and people who don't know them don't realise there's an opportunity being missed.
If you didn't know how to read, you'd find everyday life a challenge, because society expects people to know how to read. The benefit of being able to read is obvious, because important uses of reading are everywhere. Society doesn't expect you to know basic algebra, so getting through life without it is easy, and you won't even notice the missed opportunities to save money or time.
That's not because your math professor is lying about it's usefulness. It's because you chose to remain blind.
(Math people: please post good examples of using algebra, trigonometry, set theory, probability, combinatorics, calculus, etc. in Regular Life. We need a massive database to show the 'math is useless' crowd.)