Really? If you are rich enough to be able to afford and run a car, is your life really a misery?
Car owners comprise less than half the population, yet contribute disproportionately to pollution. They of course do pay a little tax depending on the amount of pollution they cause, but they dish out that pollution to all other users of the roads (including themselves) as well as noise, and death, injury and damage through misuse.
According to the government, cars are responsible for 29,000 deaths a year (see http://www.dft.gov.uk/vca/fcb/cars-and-air-pollution.asp) so the less on the road, the better for everyone. The idea behind making it more difficult to travel through urban areas by car (like closing a junction on Devonshire Road) is to encourage people to seek other forms of transport. There are plenty of options in London.
If there is such a thing as this anti-car movement you speak of, they should be applauded for trying to save lives of young and old, and improve lives of others.
This doesn't mean we should stop buying things online (or at all), but that we should think about why we are driving to the park, the shops, or (bizarrely) the gym. Only two out of five short journeys (under 5 miles) are currently made by foot, bike or public transport.
If people can't rationally come to the conclusion that they are killing others by getting in their car, then it should be more difficult for them to do so. Closing junctions is one way of achieving this.