From that policy:
3. Negative allegations of fact. Posts containing unsubstantiated negative allegations of fact about a person, company, or other organization, whether directly or indirectly referenced or named in the post, will be deemed offensive and removed. Unsubstantiated facts will include all statements which are not supported directly by a separately published and publicly accessible report, story, document, or similar item, or are your own personal experience. Information you received from another person is not your own personal experience.