Rousting citizens from their homes at gunpoint IS NOT their job, and is actually forbidden unless there is a warrant.
That's the big difference.
Citizen didn't have to ID the perp in the boat with a picture ID. He knew that someone was on his property that didn't belong there. That's the way things are supposed to work.
/johnny
It's apparent you are unfamiliar with the various long standing rulings handed down by SCOTUS on the above!