A bishop’s power includes regulating the liturgy, so (contra Corsair), he has the authority, for instance, to forbid a priest from attempting to say a Mass he’s incapable of. If a priest’s Latin is too poor, the bishop can forbid him to say Mass in Latin (in either the EF or OF), just like he can forbid a priest from attempting to say Mass in Chinese who doesn’t speak good enough Chinese. Likewise, if a priest had shown no understanding of, or willingness to follow, the rubrics of the EF, the bishop could prevent him from saying it.
The important point is that the bishop’s authority in this regard derives from (1) his power to regulate the liturgy and prevent poor celebration of Mass, not (2) some specific power to exclude the EF, which Summorum Pontificum affirms the bishop does not have.
Summorum Pontificum, however, allows the bishop to prevent any priest from publicly celebrating the EF. Perhaps that is what happened in your case.
Not quite:
EF = TLM (Traditional, or Tridentine, Latin Mass) = pre-Vatican II Mass, always in Latin.
OF = Novus Ordo = Mass of Paul VI = post-Vatican II Mass, drafted in Latin (but with different Latin texts than the EF) and able to be celebrated in Latin or any of the languages into which it has been translated, including English.