SAN FRANCISCO — The post went up quietly on Facebook’s internal message board last week. Titled “We Have a Problem With Political Diversity,” it quickly took off inside the social network.

“We are a political monoculture that’s intolerant of different views,” Brian Amerige, a senior Facebook engineer, wrote in the post, which was obtained by The New York Times. “We claim to welcome all perspectives, but are quick to attack — often in mobs — anyone who presents a view that appears to be in opposition to left-leaning ideology.”

Since the post went up, more than 100 Facebook employees have joined Mr. Amerige to form an online group called FB’ers for Political Diversity, according to two people who viewed the group’s page and who were not authorized to speak publicly. The aim of the initiative, according to Mr. Amerige’s memo, is to create a space for ideological diversity within the company.

The new group has upset other Facebook employees, who said its online posts were offensive to minorities. One engineer, who declined to be identified for fear of retaliation, said several people had lodged complaints with their managers about FB’ers for Political Diversity and were told that it had not broken any company rules.