> “one is a Jew in their heart” comes straight from the Reform/Conservative playbook.
now havos halevavos is a reform book? What this reflects is that we sometimes tend to counter the external influences. For example, some emphasize doing v beliefs in response to the religion that calls for the faith alone. Same here. As we were challenged by reform and communists, it was natural to focus on what they rejected. Good that we have Tanach and Gemorah that still has those issues mentioned.