Because taxis and cyclists are road users like others, car drivers also have to stop if a taxi has to drop off someone as long as it's quick. Same with buses, also. Or trams.
It's the same with pedestrians : if an old person walks on a small sidewalk, I will stop or slow down. Or if I see two guys carrying a washing machine.
As a pedestrian, I don't see cyclists stopping often when they ride on the sidewalk, though.
How often do you see two guys carrying a washing machine?