If reclining the seat will crush the knees of the person behind you, the seat shall remain in its upright position. The mechanical ability to do a thing is not a justification.
When that happens you're stuck with the situation of having your knees caps smashed, just so someone can tilt their seat back a few degrees.
It's a very strange situation to agree that someone should have a small privilege to the discomfort or even pain of someone else.