There were a number of Universities that did an expose of sorts on her, and the NY times, Patheos, and others published a number of articles about it. Consider everyone's agendas in all of it. The authors were clearly against divorce and not supportive of the catholic church in general. Others who support her usually have agenda's too.
The expose of sorts did validate that she did do a lot of good things for the poor, no doubt. She also felt that suffering and pain should not be interfered with, because it was an achievement, a path to understanding the sufferings of Christ. She believed that there was joy to be found in suffering. She did provide homes for the poor, places for them to die, which was helpful to them, but then did things like having her sisters bar family and friends from coming to be with the dying. Her organization does not deny these things.
I wouldn't call it sadism. A sadist would not have done as much good as she genuinely did. It seems more like a religious belief gone ary.
There is a difference between finding joy in the midst of suffering, and inviting suffering in as a path to joy. The former is spiritually and psychologically healthy. The latter is not.