As another poster said, what exactly would you expect Amtrak to do?
The train my sister and kids took to Orlando also was delayed by the exact same thing: someone decided to simply end their life on the tracks at 3am. The delay ran about 4 hours so authorities could complete all their work and the train could be cleared to continue.
In your case, there probably wasn't much at all Amtrak could have done. For the most part, Amtrak doesn't own the tracks...they are owned by freight lines and Amtrak must always yield to their trains. Often, there is only one line of track with sections of sidings periodically along the route for the Amtrak trains to 'make way' for the freight lines. There's no second track to divert to.
The car attendant told my sister that folks would be surprised just how often a train hits and kills a person; it apparently happens more than one would think. My sister's train was in August, and the attendant said it was the fifth or sixth she's had since January.
On their return trip, the train hit a rather large deer. Didn't stop for that.