Blake Lively says she has people to corroborate her complaints against Justin Baldoni ... and, while JB and his team want them to reveal their names, there's one major reason they aren't -- they're terrified of receiving the same treatment as the A-list couple.

Sources with direct knowledge tell TMZ ... it shouldn't come as a surprise that the two cast members from "It Ends with Us" who will testify in support of Blake are hiding their identities -- 'cause they don't want to deal with the abuse like Blake and her husband, Ryan Reynolds, are receiving.

Our sources say Steve Sarowitz -- a partner in Wayfarer Studios -- allegedly comparing his retaliatory plan to Israel's campaign against Hamas, plus his willingness to empty coffers to take them down, would rattle anyone ... especially those just getting started in the industry!

As you know ... Blake filed an amended complaint earlier this week in which she said multiple people from the 'IEWU' set would come forward to corroborate her claims of sexual harassment against Justin Baldoni.

She didn't reveal their names ... and Baldoni's lawyer, Bryan Freedman, blasted the whole complaint as hearsay -- from people who were "clearly no longer willing to come forward or publicly support her claims."

Baldoni’s camp tells TMZ … "Ms. Lively, Mr. Reynolds, and their paid representatives initiated this campaign which has severely impacted many private individuals, their livelihoods, and their families.

"Since they’ve yet to show any evidence and continue to blame others for the online vitriol resulting from their own actions, they are now speaking on behalf of alleged third parties who have not come forward themselves.

"Wayfarer, Justin, and their representatives have no ill will nor vendetta against anyone who speaks up in any circumstance and have first-hand experience with and empathy for the struggles of going against incredibly powerful individuals in pursuit of the truth."

Justin and Blake are both living their lives in spite of the growing legal fray ... with Justin cooling off in Hawaii, while Blake hit the Big Apple for the "Saturday Night Live" 50th anniversary special last weekend.