It's not a matter of opinion, it's physics. Here's the thing:
Air is not a good conductor of heat. If you put the interior of a car into contact with colder air for a short period of time there will be very little transfer of energy from the seats, dashboard, etc into the air. If the colder air does not have time to take up much energy it can not move that energy out of the car with the next swing of the door.
Air does not have a lot of heat capacity. Per mass, plastic and aluminium for example store twice as much heat. However, air is a gas - the mass of air moved by a door swing is tiny compared to the mass of the car's interior. You're looking at thousands of times less heat capacity in the air moved with one swing compared to the car. In other words, to cool the interior of the car by x degrees you need to heat up exchanged air by x degrees from thousands of door swings. Five will only make the initial whoof of hot air when opening the door disappear because you have openened the door several times before.
Real world experience and empiric evidence comes into play as well, but takes a back seat to highschool physics. When I quickly exchange the air in a hot car (no need for manual labor, we have wind for that) and then get in I still get a hot bum from the seat, and the dashboard still is hot. Cooling the car through airflow takes time and a lot of air.