Journalist Glenn Greenwald ripped progressives on Tuesday for claiming expertise on the subject of masks, despite having "no scientific training," and reversing themselves on whether to trust the guidance of the Centers for Disease Control and Prevention (CDC) now that it's loosened restrictions.

The CDC recently updated its COVID-19 guidance to say that fully vaccinated Americans can take their masks off indoors and no longer worry about physical distancing. But liberals have gone on TV to advise the opposite, suggesting it's one's civic duty to keep wearing a mask. Greenwald observed it wasn't too long ago that those same liberals were accepting the CDC's guidance as gospel.

"Yet it's now totally common for liberals with no scientific training to go on TV & reject new CDC guidance," Greenwald tweeted. 

Greenwald argued that such rhetoric coming from people like "Morning Joe" co-host Mika Brzezinski, who told viewers on Tuesday to "still wear the mask," and MSNBC host Rachel Maddow, is "anti-vax."

"If someone like @morningmika or @maddow or whoever wants to keep wearing masks, that is their right," he tweeted. "I have no interest in critiquing that choice. But if you go on TV and keep defending that choice, it is 100% an anti-vax message: you don't believe the vaccine really works."

Maddow recently admitted to her audience that she's going to have to "rewire" herself to not think of people not wearing masks as threats.

"I feel like I'm going to have to rewire myself so that when I see someone out in the world who's not wearing a mask, I don't instantly think, ‘You are a threat,’" she said. "Or you are selfish or you are a Covid denier and you definitely haven't been vaccinated. I mean, we're going to have to rewire the way that we look at each other."

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"The View" co-host Sunny Hostin recently said much of the same, suggesting that not wearing masks is too dangerous because it's impossible to know who has been vaccinated. Her stance changed dramatically from last April when she suggested that requiring mask-wearing could be dangerous for minorities.

It's not just media pundits, Greenwald noted, singling out Democrat New Jersey Gov. Phil Murphy for circumventing the CDC with his mask mandate.

"All ‘consensus’ should be subject to questioning and dispute. There's nothing wrong with doing it. But for most of the COVID pandemic, it wasn't allowed - certainly not culturally, and often at all," Greenwald wrote. "It's only allowed now that liberals don't like the new CDC guidance on masks."

When CDC Director Rochelle Walensky revealed the new mask guidance last week, she heralded it as a next step toward "normalcy." At the end of March, however, she warned of potential "impending doom" from coronavirus cases.

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"We have all longed for this moment when we can get back to some sense of normalcy," Walensky said. "Based on the continuing downward trajectory of cases, the scientific data on the performance of our vaccines and our understanding of how the virus spreads, that moment has come for those who are fully vaccinated."