Tech leaders are beginning to worry that Silicon Valley’s new political correctness is stifling innovation.

Silicon Valley is often referred to as the “Valley of the Democrats” because of the area’s strong endorsement of the social justice agenda — plus the fact that about 83 percent of tech company political contributions went to Democrats in the last election cycle.

Partner Katharine “Kat” Manalac told SiliconValley.com in July that Y Combinator, which has been the largest incubator for start-up tech companies in Silicon Valley, sent a form out to 3,500 local entrepreneurs to gather personal information about venture capitalists (VCs) and their attitudes toward women. Manalac added, “We don’t call it a blacklist,” but she then admitted, “that is essentially what is happening.”

Many of Silicon Valley’s moralizing progressive tech leaders over the last five months have found themselves increasingly stuck in the web of political correctness they wove to combat conservative ideas — or, critics suggest, to stifle conservative ideas.. Examples include of big names shamed out of business include Andy Rubin, who led the Android smartphone software effort at Google; top venture capitalist Steve Jurvetson of Draper Fisher Jurvetson; Google’s top lawyer David Drummond; tech blog-star Robert Scoble of Scobelizer; Uber founder Travis Kalanick; Uber top engineer Amit Singhal; Binary Capital VC founder Justin Caldbeck; former Mozilla CEO Brendan Eich; and Dave McClure, who founded the 500 Start-Ups tech incubator.

Facebook COO and progressive icon Sheryl Sandberg commented in early December that she wrote in her bestseller, Lean In that 64 percent of tech senior male managers were afraid to be alone with a female colleague, due to fear of being accused of sexual harassment. She warned that the recent witchhunt was causing a blowback against women: “We have to be vigilant to make sure this happens. I have already heard the rumblings of a backlash: “This is why you shouldn’t hire women.”

With social media swirling with rumors that new allegations are coming against more Silicon Valley tech leaders and venture capitalists, Y Combinator President Sam Altman lamented that he feels more comfortable discussing controversial ideas in Beijing than in San Francisco.

He added: “Political correctness often comes from a good place—I think we should all be willing to make accommodations to treat others well. But too often it ends up being used as a club for something orthogonal to protecting actual victims.”

Altman claims that restricting speech leads to restricting ideas and therefore restricted innovation. Concerning the future of Silicon Valley, Altman says he is seeing many of the smartest people Silicon Valley moving out, “because they feel stifled in the Bay Area.”

Ironically, Y Combinator recently saw the departure of prominent Donald Trump supporter Peter Thiel, who has become a major target of progressives in Silicon Valley.