Exactly. If you're skeptical of gun ownership, go to England and start voicing controversial opinions, or to Australia during a viral pandemic, and see how quickly you realize that "any old fool could be armed" is unbelievably important to ensure everyone keeps their basic ordinary human rights.
If you think "no cars" is a good idea, live under a government that takes away your right to public transport. It may not happen right now where you live, but if they need leverage against you, they could use that, and there would be nothing you could do.
A new government comes in and limits your ability to use it. What now? Car-free cities seem nice until they're used as leverage. No cars means massive power for a tiny number of people.
Not everyone is a troll when they disagree with you.
My biggest point on car free cities is that it is supported fervently by the people who would gain massive amounts of power over others if nobody had a car. If you're dependent on public transport, it can be taken away from you as leverage.