In the times of the Mishnah, many idol worshippers would engage in all these different types of terrible acts. They would act immorally. They would murder. So the Hachamim (the sages) set certain barriers, certain boundaries, to make sure people don’t fall into the negative ways of Avodah Zarah (idol worship).
The Mishnah says that a person is not allowed to leave his animals in the stables by the motels or inns owned by idol worshippers, because the owners were suspected of having relations with animals. One of the Sheva Mitzvot Bnei Noach (the seven Noahide commandments) is that a person is not allowed to have any form of immoral relationship, including with animals. So that applies to Jews and non-Jews as well. The Hachamim said that if a Jew leaves his animal in the stable, he may be giving it to the idol worshipper to have relations with. Therefore, he’s not allowed to leave it there.
A Jewish woman is not allowed to be secluded with idol worshippers because they are suspected of acting immorally and may have relations with her. They may commit an aveirah (sin) with her, even though this Issur (prohibition) applies to Jewish men as well. Jewish men, in front of their own wives, would act a certain way and wouldn’t go with another woman. But idol worshippers, even in front of their own wives, would go with another woman. Therefore, we’re adding to the regular prohibition of Yichud (seclusion) for a Jewish woman.
A Jewish man is not allowed to be secluded alone with an idol worshipper because idol worshippers are suspected of committing murder. They may murder him. We’re talking, of course, about a place where there are no laws and no punishment for the murder of Jews. Since the government doesn’t deal with them properly, we would be nervous about being secluded alone with an idol worshipper. But if you have a government that acts according to the law and has protective rules in place, then there’s no problem of Yichud. We don’t list this prohibition for women because even the idol worshipper would have a little bit of pity for a woman, because women are more peaceful than men. Therefore, we’re not nervous that the idol worshippers would kill Jewish women.
Other prohibitions that the rabbi set so we don’t cause more idol worship are in the following part of the Mishnah: A Jewish woman is not allowed to help an idol-worshipping woman give birth, because she would be assisting in the birth of a child who is going to perform idolatry. Therefore, she cannot help with the birth. That’s only talking about a woman who does it for no pay. She can excuse herself: “I have to get to work. I’m sorry, I can’t help.” She can come up with a valid excuse. But a woman who does it for pay—it’s her job—can’t give an excuse, because we’re nervous that it’s going to cause hatred between the idol worshipper and the Jewish people. So she actually has to help with the birth. An idol-worshipping woman is allowed to help a Jewish woman give birth if somebody is watching her and making sure she doesn’t hurt the baby. There are people standing behind her, making sure the situation is clean. But if she’s alone, the prohibition would apply to the Jewish woman: she can’t have a non-Jewish or idol-worshipping woman helping her give birth if they would be alone.
A Jewish woman is not allowed to nurse the child of an idol worshipper because feeding that child will lead to the performance of idolatry. You’re promoting the worship of idols by having this child gain sustenance from a Jewish woman. But regarding nursing, an idol-worshipping woman is allowed to nurse the child of a Jewish woman in the mother’s home, because we’re not nervous that she’s going to hurt the child. But in her own home, away from the mother, we are nervous that she would hurt the child, so that would be a problem.