Contemporary hypocrisy prevents elite members from building a prison-like dome over The Kind-of Sketchy Parts of Town, because that would have a disparate impact against groups whose shortcomings pile up collectively like a garbage heap in those parts of town -- blacks, Mexicans, drug addicts, crazies, whoever.
In the good old days, it was OK to talk about hoods, bums, "the ghetto," and so on. Shoot, if black hoods tried to mug you on the subway, you could just pull out your gun and blow them away, no questions asked. Disparate impact was not a major theme of daily public life, so you could isolate the shithole parts of town and not have to worry about race hustlers and civil rights lawyers teaming up to sue your ass.
Now, in order to build a wall to keep out group A, you have to wall off groups B through Z as well. Those kept-out groups are so all-encompassing in terms of race, sex, income, education, politics, and so on. Really anyone outside your own little neck of the woods. Hence you can't be the target of disparate impact lawsuits, reputation-poisoning charges of racism, etc. You just, uh, prefer a little more local flavor in your lifestyle.
I've only gradually come to understand this by getting around without a car for nearly two years now, which ain't so bad where I live. However, I have noticed that it's practically impossible to reach a range of places I used to frequent in a somewhat well-to-do area. It's not even Georgetown, where very rich and powerful people try to keep the hordes at bay by not allowing a metro line into their area. It's a barely upper-middle-class area with the mainstays of Stuff White People Like -- Whole Foods, Barnes & Noble, large park with joggers and doggie-walkers, etc. Nor is it a racial island, since there's no real race problem in the whole metro area.
If it were rich whites trying to keep out poor blacks, I could understand. But it's more like the SWPLs trying to keep out everybody else, including the middle / upper-middle-class people in my neighborhood, who are also white, educated, law-abiding, liberal, indie-coffee-shop-supporting, outdoors-loving, etc.
On the whole, they're not so different from the SWPLs, except for one thing -- SWPLs organize. They're control freaks, where most people around where I live aren't so micro-managing and engineering toward their own and other people's lives. Like I doubt the parents around here would lobby the school board to ban peanuts, or chauffeur their kid around from lacrosse practice to $100-per-hour test prep sessions.
That trait goes overlooked because it's usually correlated with other, more visible traits like race, income, education, etc. But here where the metro area is fairly homogeneous and egalitarian on those measures, this personality difference leaps out at you. All else equal, the OCD control freaks will take over a society. And the more that trait increases over time, the more we'll see not just this or that area walling itself off, but every one of them. Some weird containerization of half-human cargo.
The most important strategy seems to be getting the out-group to stop driving cars and rely on public transit instead. Remember, the SWPLs are happy to drive their SUVs and Priuses around their community, but if other people drive cars too, they could drive them right into SWPL country. Could we put up toll booths? Too much hassle for us every day. How about a wall with some kind of ID-based entry? Nah, smacks too much of gated community racism. Well then, I guess we could just cripple the out-group's control over their own automobiles.
Public transportation networks do not arise organically, they are centrally planned and hence shaped by whoever has the most influence. In a not-so-third-world-looking place, that means the control freaks. They may have a bus route or two go through their area, but it will not go very far outside, which would expose them to invaders hopping on. And it allows the true believers to ride on public transit without having to sit next to the public.
More, there will be few or no transfer spots near the SWPL stops. It will be hypothetically possible, if you look at the network, to get from point A outside of SWPL country to point B inside. So most of those kept out may not notice so easily, and jihadist activists will have a tough time arguing that the control freaks are aiming for social segregation. The thing is, it's going to take at least an hour and a half for what should be a more direct 15 to 20-minute car ride. And you'll have to make multiple transfers, perhaps even use different modes of transportation, stand around waiting for the next vehicle to show up, exposed to the elements, and winding all around the area.
In short, it's meaningless to talk about "access to public transportation." It's about the accessibility of point B, using public transportation. But by talking about access to public transportation, the SWPL control freaks get a chance to moralistically preen, so concerned for the plight of the common man, while deflecting attention away from the configuration of the public transit network that is designed to keep the common man in his place. It's win-win.
Even better, in the rare event that someone does notice how public transit has been used to achieve social segregation, it makes it look like a policy wrought by bad politicians. SWPL control freak residents thus get a huge cover-your-ass payoff out of the deal too.
The eco-friendly, carbon footprint talk is just rationalizing bullshit. It's all about locking the out-group members onto pre-determined paths that will effectively never allow them into Our Quirky Community. Letting them drive cars is just leaving way too much up to chance for the control freaks to tolerate it. The various measures to raise the price of owning and driving a car are part of the whole thing, but really you want them to just abandon the car altogether, and that means you need to give them an alternative, suitably sugar-coated.
I want to stress that this is not an understandable case of law-abiding middle-class whites wanting to keep out violent black hoods, and just having to take a more indirect route to doing so in these overly sensitive times. Even in homogeneous, egalitarian metro areas, we're going to see the SWPL control freaks colonizing the more desirable areas and walling everybody else out. It is more of a prelude to the disintegration of civil society than to a clash between opposing race-and-class factions.