All airlines will avoid turbulence if it's possible..if not for passenger comfort they will avoid it for fuel efficiency. That is, unless it represents a REALLY strong tail wind that will shave time off and the turbulence is light to moderate. I don't know which airline has which policy regarding passenger comfort, but all of them try to make things as comfortable as possible when possible.
Still, turbulence can cover a huge area and is sometimes unavoidable at all practical altitudes no matter what airline you are on. It's not their fault. It's beyond their control most of the time.