The Civil Rights Act of 1964, in short, prohibits discrimination against a variety of general characteristics by the government and by businesses that provide services to the general public.
Social Media sites run by formal companies should be required by law to abide by the Civil Rights Act as well, especially in regards to clients residing in the US.
Policies by such companies must comply and be upheld by law, including the Civil Rights Act. Any policy that violates these laws should be addressed.
For example, by law Non-Religious groups are considered EQUAL to religious groups without being defined AS religious. Facebook, however, defines Hate Speech ONLY against religious groups, thereby ALLOWING Hate Speech against Non-Religious groups. A violation under the Civil Rights Act.