Let’s play hypotheticals, then.
Imagine, for a moment, that this is not the first time he’s done this. Let me set the scene:
The dom prepares for an hour and a half beforehand, cleaning all the equipment, putting on her desired clothes, making sure everything is perfect for the allotted scene. (This is not an uncommon time frame or practice.) She tailors her mindset and persona, donning a mask that is harsh and unforgiving and unrelenting, because that’s what the client is paying for.
The client arrives, and the scene begins. Partway through, she teases him with a portion of her plan for the next session, so he can stew on it in between appointments, giving him something to look forward to. Instead of looking forward to it, he immediately begins to question the details - how will she do it, what will she use, will she be doing it the way he likes so that he can get his money’s worth? The tone of the scene is lost, the experience is lost, and now they’re negotiating business, because she allowed it. This goes on for 20 minutes or so, hammering out details.
She manages to bring the conversation back to the scene politely, and begins to re-create the headspace necessary to have a good scene. By the time that is done, there are only 30 minutes left in the allotted time, barely enough to squeeze in the bare minimum that they had agreed on for this session. She cannot extend the scene, because she has another appointment booked with only enough time to do the prep work for a completely different scene.
When the session is over, the client does not leave; instead, he complains that the time spent negotiating was not “scene time,” because they were not in role, and she was far too forgiving of his “saucy mouth.” He is unhappy, and wants to know what she will do to correct this situation. Having good customer service skills, she promises that next time she will take no backtalk, and that all scene time will be spent in role. He wants a discount on this session, because he didn’t get his full time, he feels - and even worse, she is now wasting time on him that she can’t afford, because she’s losing time for preparation for her next client.
So what does she do? Next time, she takes no questions and no backtalk, and when he becomes a problem AGAIN, she decides he is no longer profitable as a client, and terminates the relationship. If he had addressed his concerns in a timeframe that was not limited (in between appointments is usual, by phone or email), he would not have lost the business relationship. But because he chose to be a pain in the ass, she decided not to do business with him anymore.
There was never (in my reading) a threat of using any toy he was not comfortable with on him in that moment, or in the duration of that appointment. He had ample opportunity to stop the action at any point, and chose not to take it. He was within his rights to do so, and she was within her rights to choose not to do business with him anymore because of his negative impact as a client.
Now, all this is guesswork and extrapolation, and it could have happened totally differently. But professionals do not give up paying clients lightly, not if they are decent clients, and it seems simply likely to me that he was no longer coming out positively in a cost/benefit analysis.