The "King of Queens" actress, 51, was a part of the Church but now is very vocal about the alleged injustices committed by the organization. Remini left Scientology in 2013.
She told Daily Blast Live on Tuesday that Prepon, 41, could have used her platform to help others who are struggling to leave.
Remini told the outlet she "reached out" to Prepon but that "not everybody who has a voice uses it."
"I got people into Scientology—I promoted it most of my life," Remini explained. "For those of us who were in the public eye and who were speaking on behalf of Scientology, getting people into Scientology, I feel that we have a responsibility to do the work when we find out that none of those things we were doing was not only [not] helpful, but damaging and very harmful to people's lives."
The "Scientology and the Aftermath" creator reasoned that "not everybody feels that they have a responsibility" to try and help others.
"Some people, like Laura, feel they don't have a responsibility to speak out," Remini said. "Do I respect it? I mean, not really."
Prepon told People magazine back in August she exited the Church a number of years ago.
"I haven't practiced Scientology in close to five years, and it's no longer part of my life," the "Orange Is the New Black" star confirmed. Prepon said she and her husband Ben Foster prefer to "meditate daily, and I'm really liking it."
Last year in a long post on social media, Remini slammed Rep. Karen Bass, D-Calif. her past praise of Scientology.
"Scientology is guilty of breaking up families, abusing its staff & followers, extortion, destroying evidence, infiltrating government agencies, going after its perceived enemies. It is not like any real church. No real church has a price list for its services, costing hundreds of thousands of dollars, even millions. Businesses do. No real church denounces God (any God) as a 'lie,'" she wrote.
"No real church has a dedicated department to go after its former members with the intent to 'destroy utterly' anyone reporting their abuses to the authorities," she shared. "And policies forbidding it. No real church uses it’s tax exempt money to harass, scare into silence those speaking out or using millions upon millions to hire private investigators to watch, stalk former members, just because they can. No real church has its employees, celebrities and followers attempt to destroy those speaking out about its abuses."
Remini continued, "The victims of Scientology and its fair game tactics deserve better from you. Our country deserves a VP who fights for those who can’t fight for themselves. We need leaders who take a side for the good and decent when it’s not convenient, who are willing to fight the Goliaths of the world."