HSBC's money laundering has directly compromised the security and safety of Americans and people worldwide. They've aided drug cartels in Mexico, disregarded terrorist financing links, and hid over 19 billion dollars of transactions with Iran.
U.S. law must be applied equally across the board. A 1.9 billion dollar fine is a mere slap on the wrist for an institution that can recoup those dollars within a month. Repercussions must match the crime, and that means a greater fine for the institution, and jail time for those responsible.