I have a right to not face physical injury
If this is your honest belief, and fair play if it is, I am not doubting you, then you should
never be sitting in that seat. Life is too short and there are many other options in the marketplace. And yes of course the person in front is entitled to try and maximise their comfort given the limits of the circumstances. You may have a point on short haul, but to insist the person in front sit bolt upright on long haul to suit you is warrantly unreasonable.