San Francisco parent advocates are furious over what they call an “unvetted and illegal” ethnic studies course that was rammed through without meaningful input — citing divisive lesson plans like a “privilege wheel” that sorts student into an “oppressor/oppressed framework,” according to a legal warning sent to city leaders. The Friends of Lowell Foundation, which advocates for academic merit at San Francisco’s premier public magnet school Lowell High, blasted a year-long ethnic studies course just permanently adopted by San Francisco Unified School District — making it a requirement for ninth graders. The scathing letter accuses the San Francisco Board of Education and district leaders of quietly pushing a $7 million, required course for ninth graders called “Voices” that has largely been concealed from concerned parents. A “wheel of power and privilege” sorts individuals into categories of race, sex, gender identity and other characteristics.…