It's the classic sphere of authority defined by life, liberty, and property. Fences, and other physical or metaphorical barriers, define where we cannot rightfully trespass against others and where they cannot rughtfully trespass against us.

The American left says silence is violence, and speech they dislike is hate speech, and therefore also violence, and many celebrate the assassination of a man who was arguing against their ideology. The left as we know it here is dead to me. So is the right, for innumerable other reasons.