I am not an airline pilot
but I do think airliners will ride out turbulence because they want to stay on track to keep to their schedule, whereas a private pilot with passengers is more likely to do something about it.
Also airliners fly high where there often is clear air turbulence over long distances (the jet stream) whereas at GA altitudes, say FL100-FL200, once you are above the clouds the air is normally completely calm. I have done plenty of 4-7hr IFR flights and none of them had any significant turbulence enroute.
The longest bit I recall was a flight across the Alps, about FL170 i.e. about 8000ft above the terrain (down to the Adriatic) and there was a fairly gentle up/down ride. Nothing harsh, but a bit like being on a boat. Lasted about 15 minutes.