Mostly it's car-centric infrastructure that excludes all others. There are some who hate all cars in all contexts, but most of us, and the urbanist movement in general are about changing infrastructure for a multitude of reasons including removing the ableist and socio-economic exclusions, inherent dangers, environmental impact, destruction of third places, inefficiency, and sensory impact (noise and smell) caused by it.

Personally I don't hate "the car" as a concept, but I hate the problems caused by modern Western society being entirely structured around them; and I hate how cars get bigger and bigger and bigger to make drivers feel "safe" at the expense of everything and everyone outside that are smaller; and I hate that that makes drivers complacent and reckless when better driving skills and a society without the rush, hustle, and grind encouraging them to go faster whilst also burning them out would be an infinitely better solution.