One thing led directly to another. So the statement above is still true. You don't have to like it, but that is literally what happened.
We don't know any other details. None. We don't know what kind of fight led up to this, what this guy was going through prior, if there were in fact mental health issues, etc...
Maybe he just liked tall grass or was going for the "natural landscaping" look. Whatever else was going on, the GOVERNMENT got involved and now the guy is dead.
Hundreds of thousands of times a year, people interact with government agents, and no one dies, Hundreds of thousands of times a year citizens win over the government. The common denominator in all these interactions is that they don't shoot at people because they disagree with them.