The board opened some schools for a single day at the end of the school year, just to qualify for state funding to pay teachers.
The board spent time (whilst schools were closed) deciding how to rename schools, something which has zero impact on educational outcomes.
The board has a member who made racist remarks on Twitter and, despite not losing her position, is suing the school board: https://missionlocal.org/2021/03/alison-collins-school-board...
These are other reasons to be dissatisfied.
More concerning to some people is that becoming a member of the SFBOE is a common launching point for the SF Board of Supervisors.