I understand your answer about non-Jews using the Mezuzah as a token or show of their love to the Jews. But do you think it is wrong for Christians to use a similar token in their home as a reminder as they come an go that God abides with them and that there is truly only one God?
Shalom, Thank you for your question (I apologize for the delay in answering – you have caught us in the middle of the Jewish holiday season). As I wrote in my first answer, it is not appropriate that non-Jews put up mezzuzot. However, there are other reminders that one could have in their house as reminders of G-d. For example, pictures, art, or verses from the Bible. May you be blessed with much holiness and joy.