Why the hell do you care about how people dress in an airport? They don't care about how you dress. The number of people who are able to use air travel has expanded mightily over the years, and that is reflected in the fact that everyone doesn't feel the need to dress like they are at the country club to board a flying conveyance. It's not a cotillion or the board meeting, just someone going to see grandma in Cleveland or get hammered at Myrtle Beach. A lot of the pilots don't even wear a tie anymore.

I regularly travel by Amtrak, and I have seen some real characters but never the type of behavior you are talking about. Everyone is generally very nice or minds their own business. You can keep your troublemakers in first class with you.