Actually, they are not. When I was growing up in the 1970s we used to go coon hunting. We never asked for permission to cross into other people's property, because raccoons were property destructive and the famers wanted them gone. However possums were left alone. The only crime that they were accused of was eating chicken eggs and not very often.
Several years ago, I read that one of the main food sources for possums are ticks. They eat an unbelievable amount of them. Where I live, we have a serious problem with tick diseases. I have a possum that regularly patrols my backyard. Since they only live 1 to 2 years, I am guessing that my property is a part of a possum's family territory that gets handed down to the next generation. I have lived in my house for almost 20 years and is covered with a lot of trees and undergrowth. I have never seen a tick within my fence line.
I used to be awakened at night by animals coming after chickens. One hen had a nest outside my window. Coons would usually grab a setting hen. One night, I heard the hen take off, in a panic. I shined the gunlight out the window and saw a ‘possum fleeing the scene. I’m sure the hen scared the crap out of it.
They're common, here.
We leave them alone.
Them and deer are the most common roadkills, unfortunately.
Interesting that ticks are a food source.