as a tourist, I have used Amtrak a few times and intend to again in the future. Some of the longer journeys are a great way to travel - much better than air if you want to see the country. I don't dispute there is a subsidy, but I have spent several thousands of $$ in the USA that I wouldn't have done if there hadn't been able to include the journey in my itinery.
I try to keep out of non-chip debates so I promise to keep quiet now , but I would hate to see the end of passenger trains in the USA. I'd keep coming of course (great place for vacations), but just not as often.
Take care
Jason