"We are literally under attack for not just supporting the other candidate. Now I'm with Monica Lewinsky with this: bullying is bad. She's actually dedicated her life now to talking about that," Dawson had said, before introducing the Vermont senator on-stage at a rally here.
She added: "And now as a campaign strategy, we are being bullied and somehow that is okay and not being talked about with the richness that it needs to (be)."
The actress and activist covered a wide range of topics, but honed in on what she calls a "media blackout" of coverage of Sanders and recent revelations that a super PAC supporting Clinton, Correct the Record, is correcting Reddit threads.
Sanders defended Dawson's performance overall in an interview with CNN's Jake Tapper on "State of the Union" Sunday,
"Rosario is a great actress and she's doing a great job for us," Sanders told Tapper. "She's been a passionate fighter to see that we increase the voter turnout, that we fight for racial, economic, environmental justice."
But when pressed by Tapper if it was OK for her to bring up Lewinsky, Sanders said: "I have no idea in what context Rosario was talking about her. But I would hope that all of our people would focus on the real issues facing working people and the massive level of wealth and income inequality."
Earlier this week, super PAC Correct the Record announced a project called "Barrier Breakers 2016," which they describe as a task force partially designed to help Clinton supporters "push back on online harassment." The organization is allocating more than a million dollars in this effort.
In response to Dawson's criticism, the super PAC defended their campaign.
"This is the farthest thing from bullying -- posting positive graphics about Hillary is our job," said Elizabeth Shappell, communications director for Correct the Record. "The Bernie supporters are intimidated by a graphic that says 'Love & Kindness' or #ImWithHer?"
In the past several years, Lewinsky has become an activist speaking out against cyber-bullying, speaking publicly in a TED talk last year about her experiences.
Sanders, for his part, steered clear of addressing the Lewinsky comments in his speech, but did thank Dawson when he took the stage. Sanders campaign manager Jeff Weaver had no comment for Dawson's remarks.
Clinton campaign press secretary Nick Merrill said their campaign will "absolutely not" address Dawson's comments, but suggested, "You could ask the Sanders campaign why they encourage this vitriol in the vicinity of their candidate by staying silent."