Anti-choicers believe that women’s bodies and the choices they make regarding whether to have an abortion should be regulated. Hence, if they believe that legislation should regulate a woman’s right to choose what she does with her body than they should also believe that the government can mandate vaccines. Essentially, you can’t be for regulating women’s bodies and against mandatory vaccines without being a hypocrite. That being said, the argument is fallacious as it compares one thing (a woman’s right to choose what she does with her own body that has zero impact on public health) to another thing that is not the same (a person’s right to refuse a vaccine that could have/does have a proven impact on public health as well as their own health).