An experience at IKea today

Ella has been asking to go to IKea. She wants to go to the playground and play. My mom and dad decided to go today since they were looking for something. We all went to Ikea shopping. I thought it was going to be a nice and relaxing afternoon, little did I know...
There was a little girl crying pretty loudly. It was not a big deal even though her crying would make people turn heads to see who is crying. But, her mom's reaction was absolutely unspeakable and unreasonable. Her mom was yelling "哭什麼哭!" repeatedly in front of everyone. Not only that, she slapped the little girl! It made me wanted to run up and stop her! But, my mom had stopped me from doing so.
I can't and just can't understand!! This kind of behavior SHOULD NOT be tolerated. No one, and no one, under no circumstances should be slapping their children in public! I am in shock, just absolutely in shock. It's been about 3 hours since then, I am still in shock!