That is a gross oversimplification of Mother Teresa. I’m no fan of hers, but let’s dislike her for truthful reasons rather than exaggerations.
She never reveled in anyone’s suffering, though she did remark that suffering brings us closer to God, which I would consider an unhelpful stance at best.
She ran multiple hospice care centers because no one was doing anything and people were just dying in the street. She had extremely limited resources and could only provide limited medical care as she wasn’t a doctor and again, I say this with intended emphasis, literally no one else was doing anything to help.
She saw unimaginable suffering and did everything in her power to reduce that suffering to the extent of her ability and resources, which was far more than anyone else was doing.
I don’t think she’s a saint, but I think her goals and efforts were laudable even if her beliefs and methods were less than ideal.
This Wikipedia page highlights the controversy surrounding the quality of medical care, but also shares the counter argument, which is that they struggled with the same problems as the rest of healthcare in India and were treating people no one else would.