A couple of thoughts ...

1) IMO, one thing that minimizes knee stress is to move one's knees straight up and down directly over the feet. For some people, that's brushing the paint. For others, like me, it means installing peal extenders. I was having knee pain for a few years. Since I installed the extenders last year, my knees go up and down directly over my pedals (pinned flats), and my pain is virtually non-existent - but YMWV.

2) I don't know what you mean by 'rocking your hips.' I think people are talking about bending forward using your hips as the hinge, which keeps your back pretty much oriented the way it is when you're standing or sitting straight. Not bending your back helps the vertebrae and discs, I believe.