It's bad to profit off of a tragedy.
Don has information about deadly viruses and drug companies before a pandemic.
Don wants to make money.
Don funds his own research into a vaccine for a deadly virus and sells it so people can get it.
Don works to plant a deadly pandemic while investing in certain drug company's stocks related to the virus.
Many people are prepared for the pandemic and don't get sick and love Don a lot.
Many people die and get sick and people resent Don profusely.