My charitable interpretation, having talked to a lot of people about this stuff (and having lived in the rural US, NYC, and European cities), is that much of the US has been so car dependent for so long now that many people just lack a basic frame of reference for what daily life can look like without driving alone in a car to do everything outside the house.

Through the lens of a car being the only way that anyone you know has ever gotten around, parking is sort of a strict necessity. "How can you go anywhere if there's nowhere to park when you get there!?"

Meanwhile in the time since these laws came to be, we've roughly tripled the number of miles Americans are driving while the population has grown ~60-something percent, so there's more competition for street space than ever, people are spending tons of time in traffic/looking for parking, which creates a scarcity dynamic that freaks people out about any proposed changes.

The idea that getting some people to use other transportation modes could improve the daily experience for people who genuinely prefer to drive doesn't really click, either, because there's no frame of reference for getting around outside of a car, it's an abstract concept that people would actually do it. Even for people who've visited transit-rich/walkable places but never lived in one, there are often conceptual gaps—like the cadence of getting/carrying groceries, or the idea that bus/subway trips replace car trips 1:1, rather than the bus being a link between walkable areas.