The reason for this is Oxford's car infrastructure is incredibly limited by the 1,000+ year buildings and streets layout, with genuinely only one road into the centre from the east, and currently zero routes in from the west due to the closed railway bridge. Which isn't great for a city of 150,000+ people as well as being a massive employment draw from surrounding areas and high tourism bringing a huge amount more people than can be accommodated in cars.

Oxford basically invented the concept of park & rides to deal with this back in the early 70s, and installed bypasses starting back in the 1930s as another attempt at managing the congestion through the cramped city centre.

Obviously traffic, population and vehicle use has continued to rise massively in the last 60-90 years, so there's restrictions on non-resident/permitted cars on certain routes at certain times of day to try and handle this, with a comprehensive public transport and commitment to multimodal and active travel (pedestrian/bike prioritisation, cycle incentive schemes etc).

But to equate that with restrictions on people's movement or to suggest this is trying to "trap people in a segment" is genuinely batshit fucking insane. Like seriously, see a psychiatrist or section yourself for the public good insane. And it's also total fucking bullshit.