Similarly, a sure-fire way to tell someone hasn't lived in a place where you haven't needed a car for every aspect of life is when they criticize anti-car policy without engaging with the deeper reasons behind it :)
I think a lot of the pushback against cars have to do with the popularization of human-centric design movements that question the assumption that cars are the pinnacle of transportation that American cities have operated from since about the 1950s. An easy example is the idea of "induced demand" [1] that shows even from a pure engineering perspective that the cost-benefit math for cars has long been unfairly weighted towards cars by outside forces.
We're seeing a lot of pressure around housing and energy and social policy in general which in turn is making us question decisions we've made, culturally, in history, like can we really sustain the building of less dense housing for our growing population? Does it make sense to give every family 0.75 acres of grass, 400 sqft of driveway and a 2 car garage, when those things are only used some of the time? Might there be better ways to approach the utilization of that space as a population?
I'm rambling now, but I get frustrated when people dismiss concerns like that out of hand. Can the US ever totally get rid of cars? No, not for a hundred years at least. Having a good 80 years of city planning being focused around every adult having their own vehicle is of course going to e difficult to move away from, and there are certain lifestyles (rural living, farming, regions where building trains is more impractical) that it'll just never be a great idea... but I still think it's worth interrogating these assumptions we've carried to see if there's a better way we could be living life.
[1]: https://en.wikipedia.org/wiki/Induced_demand#Effect_in_trans...