This is really disingenuous. The poor people left long before the transformation started because there was no where for them to live. The housing collapsed pushed most of the land lords out of business and the buildings were left vacant. The article itself says the population of the neighborhood fell to under 5,000, in a city of 300,000.

Most of the buildings in the neighborhood were empty and collapsing. Renovating the dilapidated building and infrastructure and bringing in new tenants is what seems to have had the biggest impact.