Because the whole purpose of Christianity, the whole purpose of religion is daily living. A preacher has the job of applying the Gospel to big and small. So let me apply it simply to big and small. Ezekiel's prophecy portrays a dark picture of shepherds neglecting their sheep. Not going after them to find them.
Shepherds just have to do that, because sheep wander.
When I was a small boy I didn't have sheep around, but I went to my grandmother's ranch in South Dakota. And my cousin would get up every morning and go find the horses. And they were always in one of eight places. Maybe he had to go to eight places to find them. They wandered around because they always did that.