the business is preferentially participating in the customer choice
customer choice is also covered by the 1964 civil rights act, it’s just nearly always unenforceable unless someone goes on a racist/sexist tirade
when insurance companies allow people to filter for male and female doctors, they’re allowing people to prefer both options, so they’re not preferentially participating in the choice like Lyft is here. And, there are medical specialties where one could argue that being either male or female was a BFOQ. Being a taxi driver doesn’t involve one’s genitals like being an obstetrics patient does. If you are using your genitals to operate your car, you’re doing it wrong.