That is true, many people can get violent even over something that isn't their house. I think another important factor is also how other people empathize with the "victim" as well. If someone was the victim of home invasion people would feel more empathy towards them compared to someone who chased down a person who walked on their empty plot.
No one is challenging their ownership of either properties, but the situations are wildly different.
That's not rare, that's straight up raw.