Mistress Iside required her slave to be logical, but he was not. She was disappointed in him, and she felt that she had to do more to make him change and improve himself. That is why she cruelly had him eat her poo. He was turned into a human toilet and had to endure a lot of degradation. He had no choice but to eat the shit and to change as well.
Mistress Iside does not like to deal with clueless losers. She met this one and she did not want to continue dealing with him. She had to make sure that he regretted being one. That is why she cruelly forced the guy to eat her shit and to be her human toilet. In no time, he regretted what he had done and promised her that he would change like she wanted him to.
When mistress Iside needed to punish this loser for what he had done, she had to do it in a way he would never forget. That is why the mistress chose to use her shit to do it. That way, the punishment would be out of this world and he would never mess up again. So the mistress cruelly took a shit directly into the mouth of the guy and he ate it.
Mistress Iside does not like liars because lying is deliberate. So she had to teach this guy a lesson and she did it in a way he never expected her to do it. The mistress turned the guy into her shit slave and she fed him poo. The guy was shocked because it never occurred to him that he could be turned into a human toilet. He learned his lesson.