Stare decisis does not apply to the Supreme Court. It can not because it is the highest court. That fact used to be taught in high school American history.
Wrong. Stare decises applies to all courts. All it means is respect precedent.
Then, you were misled. Stare decisis is applicable to all court cases, regardless of the court.
Courts attempt to maintain and develop previous standings. If that previous standing was bogus, then it should be ignored and replaced with sounder reasoning.