Some people feel that when they are dealing with an employee, they are 'entitled' to treat them like 'servants', and are 'safe' in dishing out poor treatment of them, and speak to them in a manner that they wouldn't dare, if they just met them off duty on the street, somewhere...
On the other hand, I also agree that the long interned corporate culture at Amtrak in particular, gives some employees the attitude that they are 'entitled' to their job, that the passenger is an imposition on their day, that they are not paid by the passenger's, but rather by 'the government', and that they can get away with rude behaviour that would not be tolerated in better managed companies.
Again, this is not true for every employee, some of whom still take great pride in their occupation, despite often peer pressure to do otherwise...