Understanding the motivation behind the Pharma hack is unfortunately a rather easy question to answer. It is all about the money
Once upon a time hackers were bored teenagers who wanted to show the world that they were cleverer than everyone else. They used computers to feel in control of, and to show their superior understanding of the technology that they knew one day would be everywhere.
Fast forward 20 years, the technology is everywhere and no-one really cares if someone else feels they know it all. A new breed of criminals are exploiting the internet for financial gain. At the end of this process an interlinked network of computers are passing traffic to a possibly legitimate company who pays an affiliate fee, a small commission, in much the same way that Amazon does to traffic referred to it. The sites in the network are all hacked, as is the final site in the chain that bounces the traffic on to the final affiliate. Thus you have revenue with zero hosting costs or other associated business expenses. A truly parasitic arrangement.
Not only that - but legitimate sites potentially face a loss of standing in their respective fields and potentially have significant costs associated with de-hacking their website(s).