Ruby Rose Says Sydney Sweeney Is the Reason 'Christy' Tanked

Critics aren't the only ones trashing Sydney Sweeney's new movie "Christy" ... actress Ruby Rose just shared her thoughts about the flick, and they aren't positive.

Ruby posted a message on her Threads account about the maligned movie on Monday ... she said the flick's original script was "life changing."

Ruby claimed she was attached to play "Cherry" -- unclear if she meant to refer to Christy Martin, the subject of the film, or whether there was another role that didn't make it the final cut -- and wrote that much of the feature's cast members are gay.

Sydney ended up in the starring role, and Ruby lashed out at the "Euphoria" star. Ruby indicated the LGBTQ+ community is not a fan of "someone who hates them, parading around pretending to be us" ... writing "You’re a cretin and you ruined the film. Period. Christy deserved better."

"Christy" had one of the worst opening weekends for a major motion picture, taking in an underwhelming $1.3 million, according to Variety.