Like many nonprofits, membership of the @osi board of directors is technically down to the existing board choosing to appoint new directors. OSI "membership" (in the sense that donors can become "members" of the organisation) isn't a thing that's defined by the by-laws, it's a process that the directors have chosen to adopt. As such, the elections that members participate in are just guidance for the board's decisions, rather than anything they're obliged to respect.