A rep for the "Euphoria" actress called out Carol Baum for her recent remarks that classified SS as "not pretty" and not a good actress, saying, "How sad that a woman in the position to share her expertise and experience chooses instead to attack another woman."

The rep adds, "If that’s what she’s learned in her decades in the industry and feels is appropriate to teach to her students, that’s shameful. To unjustly disparage a fellow female producer speaks volumes about Ms Baum’s character.”

Sydney's former colleagues have also come out to speak up on her behalf -- including producer Teddy Schwarzman, who worked with Sydney on "Immaculate." He responded to this slam as well, saying Sydney is not only talented, but incredibly humble and kind ... and a badass scream queen too.

As for Carol herself, she's already expressing regret over the whole thing -- telling TMZ she wishes she never would've made her original comments, and that crapping on an actor like that in public usually isn't her style.

Carol -- who has movie credits under her belt such as "Father of the Bride" and "Buffy the Vampire Slayer" -- goes on to say she's been getting a ton of hate mail over all this.

As you know, Sydney's currently Hollywood's IT girl, with her roles in "Euphoria" and "The White Lotus" catapulting her to fame -- and a ton of movie roles that have followed since. She's been in rom-coms and horror flicks of late ... and is a very busy bee.

Now that someone's called her out over something so shallow, H'wood is coming to her defense.