Not only that, but they presumably have never ridden on a train before.

Every Amtrak train I've been on (which, of course, is not the model of efficiency) takes on the order of two or three minutes for most intermediate station stops, if not less. The train stops, people leave, new passengers enter, and it starts rolling again. Stowing/gathering belongings, getting seated, lining up at the exits, and ticketing is all done while the train is in motion. It's not like having a flight layover.

You also lose time by slowing down and speeding up but that notwithstanding, you may have fewer intermediate stops with HSR (as is the case with Acela vs. Regional service) but you can't cut out intermediate stops. All you have to do is look at Shinkansen routes.