Genuinely suicidal people don't threaten to commit suicide, they just do it. These people tipped their hand by coming off the roof without Foxconn conceding to their demands. If idle threats to commit suicide are a surefire indication that someone's being mistreated, then millions of teenage ex-boyfriends and ex-girlfriends are mistreated, too.
Threatening to jump off a building shows even less conviction than a genuine hunger strike (which will kill you more effectively than picketing on a rooftop making idle threats). IRA terrorists have engaged in hunger strikes to get released from prison--does that mean it's abusive to imprison terrorists?
The Chinese attitude to suicide is completely different to the one in the west, which everyone commenting here is missing. Worker suicides would cause a tremendous loss of face for Foxconn while preserving the face of the workers' families. The point of an anti-suicide contract is not to prevent people from feeling suicidal but to prevent the individual who signs it from holding that over Foxconn as a threat. If someone committed suicide after signing such a contract, the contract has priority and the loss of face would be from the worker's family.
Not everyone who is suicidal does so because they are mentally ill. People kill themselves for political causes, too. It's kind of a thing for monks to set themselves on fire as a means of political protest.
Threatening to jump off a building shows even less conviction than a genuine hunger strike (which will kill you more effectively than picketing on a rooftop making idle threats). IRA terrorists have engaged in hunger strikes to get released from prison--does that mean it's abusive to imprison terrorists?