Every politician in need of some press is jumping on the recent United Airlines fiasco. To call for congressional hearings or a federal investigation is a waste of time and money.
The passenger is going to be financially compensated for far more than he would normally have received and the other passengers will no doubt get some lucrative travel and/or financial compensation. United Airlines has and will suffer financially and publicity-wise from this incident.
Let the civil courts deal with it and move on.