Judeo-Christian doctrine also has prohibitions against theft and murder. Should we throw those out?
There's an overlap between secular and religious prohibitions, and there's no easy answer as to which rules are "religious" — you're just reflecting what's in your head as "obviously secular" and "obviously religious", and that's not how all other (secular) people view the world.
Revealing someone's secrets, is illegal in religion, yet legal in law.
While secularism have rationalized certain religious rules in their own interests like "your right to throw your arms ends just where the other man’s nose begin", they definitely did not originate with them. And though they have not rationalized everything, individuals sourcing laws from religion does not violate freedom of religion principles.
OK and what about welfare, or medicaid? Clearly a reframed version of tithing for the poor from a lot of religious traditions. Do you think we should drop those because they (a) overlap with religious teachings and (b) aren't libertarian?
Charity and taking care of the poor didn’t start with religion. Archeologists have found evidence that cultures took care of people with broken legs until they heeled thousands of years before modern religions were invented.
There's an overlap between secular and religious prohibitions, and there's no easy answer as to which rules are "religious" — you're just reflecting what's in your head as "obviously secular" and "obviously religious", and that's not how all other (secular) people view the world.