hello I don't understand why the mavic 2 air doesn't have a counter reaction to the obstacle .. wouldn't it be more correct?

APAS does what you are asking for — it navigates around and obstacle if something is in the path of the location the drone wants to be in.

If you are flying the drone under your own control, the drone will merely stop to avoid a collision. It doesn’t know where you eventually want to wind up, it’s up to you to fly there.

Hello there Andytom69. Thank you for reaching out and for these information you have given us. The DJI Mavic Air 2 is equipped with the Advanced Pilot Assistance System 3.0 ( APAS 3.0 ) feature and it is available in Normal Mode. When APAS is enabled, the aircraft continues to respond to user command and plans its path according to both control stick input and the flight environment. APAS makes it easier to avoid obstacle, obtain smoother footage, and gives a better flying experience. Keep moving the pitch stick forward or backward. The drone will avoid the obstacle by flying above, below, or to the left or right of the obstacle. The drone will also respond to other control sticks movement simultaneously. When APAS is enabled, the drone can be brought to a stop by pressing the Flight Pause button on the remote controller or tapping Stop on the screen in the DJI Fly. The aircraft hovers for three seconds and awaits further pilot commands. To enable APAS, open the DJI Fly application, enter System Settings>Safety, and enable APAS.