"I spoke with the workers at Lonmin Platinum mine to get their side of the story," James said in a statement.
"They described a situation in which the quality of a worker's life is contingent on being aligned to the correct labour union."
Miners told him that National Union of Mineworkers (NUM) members got better jobs, better access to decision-making and "the ear of management".
They said members of the rival Association of Mineworkers and Construction Union (Amcu) did not enjoy the same privileges.
"Widespread intimidation is accepted and has become a way of life for Amcu members," James said.
"The violent and illegal action of the strikers can never be condoned, but the fact is that the members of Amcu were sick and tired of being relegated to outsider status."
James said the shooting at Lonmin was an example of insiders against outsiders and that this defined South Africa's socio-economic landscape.
"If an insider-outsider dynamic was responsible for creating the tinder box, then it was the institutional failures, failure to mediate and emotional policing, that provided the spark," James said.
On Thursday, police shot dead 34 people and wounded 78 others while trying to disperse protesters encamped on Wonderkop hill.
Ten people, including two police officers and two security guards, had already died in the week before the clash.
On Monday, opposition party leaders visited the Wonderkop squatter camp, where mineworkers and residents congregated.
Congress of the People leader Mosiuoa Lekota said their concerns would top the agenda at a special sitting of Parliament on Tuesday.