Nobody bothered them until they tried to use the bathroom without buying anything. It's a very common policy, especially in major cities, to require purchase to use bathrooms. When they refused to buy anything or leave, they were trespassing. The employee told them they called the cops because they were trespassing, they didn't care. The cops gave them three chances to leave, they didn't care. Then they were arrested.
Have you ever done anything like that?
I'm going to disregard your comments about my race and my personal experience with police.