Lady Scarlet and her friends wanted to punish this guy because he had been taking them round in circles and they were tired of it all. They had to punish him and they did it with their ball busting fetish. Lady Scarlet led them in doing so and it was super fun for them. The poor guy did not have a say in the matter and he had to do what he did.
Lady Scarlet and her friend mistress Gaia wanted to ball kick this guy and teach him a lesson he had never been taught before. He did things the mistresses did not like and the worst of it was betraying them. They were not about to turn a blind eye to that as they did to other things so they taught him a cruel lesson by forcing him to endure kicks to his nuts.
Lady Scarlet wanted to make sure this guy was the sort of person she needed to hire. And she went ahead to test his pain threshold. That is why she chose to ballbust him. She closely watched out for how he reacted to the pain and she knew that he was the guy she wanted as he seemed to have a high pain threshold. He did not cry even though it was painful.