Having been an Amtrak customer since 1971, and a frequent customer over the past 20 years, I don't think there's an "attitude problem" among Amtrak customer-facing staff that's any worse than in other service industries. I think I can count the number of customer-facing staff with "bad attitude" on the fingers of one hand, well, I might need to use a couple of fingers on the other hand. I mostly ride on the NEC, bust I also ride the other eastern state-supported trains and try to get in at least one long-distance trip a year. Most of the frustrations I've had with customer service appear to have causes outside the customer-facing employees control: decreases in staffing levels, delays, cafe car or diner running out of what I wanted to order, the selection and quality of the food, etc. Of course, I don't expect a waiter or sleeping car attendant to be hovering about me always at my beck and call to satisfy my every personal whim.
I've had a lot of experience with "gate dragons" at Washington Union Station, especially during the period when they were actually looking at tickets. They were usually friendly about it, but the policy of having everyone line up and wait until someone looks at your ticket is inherently stressful for everyone concerned. I got the idea that some of them were as annoyed at the process as the passengers. They did sure seem happy when the policy was changed to eliminate looking at everybody's ticket and the lines move faster, too.
In all my years of Amtrak travel, I encountered exactly one conductor who was on what I would consider to be a "power trip," and displayed a "bad attitude" towards customers. I had another conductor throw me off a train because I had an "unreserved" ticket, and the train had switched to being all-reserved. (This was when they were converting all Northeast Regional trains to reserved service only.) I suppose he was justified in kicking me off, but he was a little rude about it. That's all the troubles I've had with conductors.
Compare that with an experience I had flying United Airlines in October 2001. We were lined up in San Francisco Airport with the mother of all long security lines and people were really complaining. I think some people might have been confused about the configuration of the line (which snaked and curved around the airport), or maybe some of the were really trying to butt in front of other people without being too obvious about it. Anyway, there was a certain amount of dissension and a (non-uniformed) United employee came out and threatened to have all of us arrested! Now that's a "bad attitude!" And then we finally got to the gate, we had a problem with one of our reservations because -- who knows? But my wife was on a different reservation from my daughter and me because she flew out a day later than us. They did take care of that one to our satisfaction, but the whole trip was pretty stressful.