The evidence does not support this claim. Bears commonly sit on their haunches on the ground, logs, rocks, or other natural surfaces, but there is no credible evidence that they usually sit on chairs. The chair examples are isolated novelty incidents, not typical bear behavior.
Caveats
The word “usually” requires strong population-level evidence, and none is provided.
Do not confuse a bear’s normal upright ground-sitting posture with sitting on a human chair.
Most chair-related examples come from anecdotal viral media, not wildlife science or behavioral studies.