Why is your right to prevent the person in front of you from leaning back greater than their right to lean back?
Well it's not a simple matter of rights. When the person in front of me reclines, they exercise their rights to my great discomfort.
As I said, I don't fit easily into airplane seats. When someone reclines it means my knees are wedged into their seatback. If I'm lucky I'll be able to move my carry on bag and extend my legs under the seat in front. But often this isn't possible.
Why should someone gain a modest comfort at my expense?
You make a good point about negotiation. But, frankly, I think the onus should be on the recliner to ask "do you mind if I tilt my seat back?" After all, they're the ones looking for a privilege.