You can probably find a guild that is OK with the level of performance of sub-standard specs.
Maybe, but refusing to play your class in a spec that is better for your group, and then having issues seems par for the course. The whole situation seems like a case of bad fit, imo.
Of course, if people who are playing classes with specs doing the same role, but out-performing by large margins are competing for the same gear, or are put in a situation where people who are performing vastly worse are competing for the same gear, I could imagine they would go elsewhere.
Not every team is going to be, or has to be aiming to be at the level of a professional, some teams are going to be aiming for the junior-level. The playstyle, practice, etc. of either of those teams is going to be quite different from a beer league.
Mismatching preferences and goals between individuals and organizations can make for an all around uncomfortable experience. It sounds like the OP would like to play Ret and be treated equally as a DPSer for loot priority as a DPS Warrior or Rogue.
Maybe find a guild that aligns with those values.