Facebook CEO Mark Zuckerberg acknowledged during a senate hearing Tuesday that the Silicon Valley was an “extremely left leaning place,” but he denied that Oculus Rift founder Palmer Luckey was fired because of his openly conservative views.

Zuckerberg was responding to a blistering line of questioning from Sen. Ted Cruz, R-Texas, who said a “number of Americans” were concerned about tech companies like Menlo Park’s Facebook having a “pervasive pattern” of “bias and political censorship” against conservative views and causes.

Zuckerberg acknowledged that “Silicon Valley is an extremely left leaning place” and that it was a fair concern “that people would have at least wonder about.”

But Cruz brought up the sudden 2016 ouster of Oculus Rift virtual reality headset creator Palmer Luckey after it was disclosed he financed an conservative anti-Hillary Clinton, pro-Donald Trump group called Nimble America. This was after Facebook bought Oculus for $2 billion in 2014.

Facebook has not formally acknowledged that Luckey was fired. But when Cruz asked why Luckey was fired, Zuckerberg said, “it was not because of a political view.”

Zuckerberg is in the first of two days of grilling on Capitol Hill as top lawmakers seek answers about the Cambridge Analytica scandal.