As per the article, Goldman Sachs just looked at their books to understand the business model, then started offering their own version of the service.

Doing what GS always does: take someone else's crap, wrap it in gold foil and serve it on a silver platter in the guise of 'legitimacy'

Goldman Sachs did even worse, they copied their business model and started their own department/company..

As others noted, it probably would've been more ethical just to buy the company outright, not simply doing "intellectual capital front running" they've frequently been accused of doing with actual capital.