Soz: I told him not to mention the elephant.
Soz: Can I go home?
Richard: Oh, you're going. Your going.
Richard: Dance at my party.
Richard: You know why people give kids drugs? So they can control their minds. 'Cause they're fucking weak-minded themselves.
Answer: Because the gang did not expect Anthony to hang himself. They told him that he couldn't move from where they left him. I presume that the drunken/drugged up gang will have been laughing and telling everyone what they had just done to Anthony. Then later they would hear the tragic turn of events and try to keep it quiet. But it would be too late then and people would talk about their involvement.