For some, Breitbart’s inclusion among its select news publishers is proof of Mr. Zuckerberg’s, and his company’s, political biases. Judd Legum, who publishes the newsletter Popular Information, reported recently that three Republican employees in the company “call the shots at Facebook” and that the social network “has repeatedly taken actions that benefit Republicans and the right wing.” Progressive critics have suggested that Mr. Zuckerberg is a Republican and that his company’s ethos leans to the right as well. “Facebook is a conservative outlet,” Adam Serwer, a journalist at The Atlantic, tweeted last week. “When conservatives criticize, they solemnly and apologetically promise to do better. When liberals criticize, they tell them to shut up.”

Facebook’s decision to include Breitbart among its select publishers is clarifying, though perhaps not in the way many critics have suggested. It’s not an indicator of secret political bias; instead, it’s a small window into how Mark Zuckerberg and Facebook see the world. Here, the realms of government and media aren’t levers to achieve some ideological goal — they’re mere petri dishes in which to grow the Facebook organism. And when it comes to Facebook and Mr. Zuckerberg’s end game, nothing is more important than growth.

Growth has always been the end game for Facebook.