No, you're not an antiquated old person.
I get grumpy, too. There are several very popular bike routes near me. I always watch for bikes when driving. I watch them blow through 4-way stops, forcing cars to slam on their brakes, flipping off drivers who honk; and I think "Thanks, a**holes, for making the rest of us look bad."
These (rightfully) p.o.'ed drivers are the ones I will have to cope with when I ride my commute.
I do my best to be a Good Will Ambassador when I ride, because weekend-warrior BS like what you saw leaves the rest of us with a real uphill battle for recognition.
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson