Respectfully, without judgement, your perspective may be wildly skewed because you’re American (going by your post history). I suspect the negative externalities in a society built around cars don’t register with you because to you it is the normal state of the world. As a Dutchman, I grew up in a built world that is based around the human scale and to me your parent’s claim comes across as astonishingly obvious.
The Netherlands has 513 cars per 1000 people compared to the US rate of 779. A significant difference, certainly, and it's plausible that there's a threshold effect where a society built around 50% more cars faces unique problems. But this doesn't at all seem consistent with the original idea that automobile technology itself is bad.
I suppose in the Netherlands they use carts and horses to stock up the supermarket? To transport coal to the powerplant (or the wind turbine blades to where the wind turbine will be built)? Surely a bicycle isn't enough for that.
You might be only talking about personal cars, but you've got to remember that trucks share the same infrastructure cars use. Modern city wealth wouldn't be possible without engined vehicles driving on roads (maybe if you went really crazy with rail that could be exception). You take away personal cars and either the infrastructure stays or your city wouldn't be possible anymore either.
But even beyond that - personal cars provide a level of freedom and capability to the general population that no other technology can match. Trains suck, buses suck, passenger ships suck, planes are uncomfortable (but otherwise pretty good). Bikes don't work with long distances, multiple people, the infirm, winter (riding in the winter is a great way to get injured, two-wheeled vehicles don't do well with ice), bad weather, if you need to be presentable when you arrive. Oh, and bikes get stolen. Constantly.
I didn't really say what my perspective is on whether the suburbs are good or bad or cars are good or bad. I think there are plenty of reasonable arguments as to whether they are or not. What I am dubious about is that they are somehow the source of some hand-wavy "widespread" mental health issue in America.