I haven't read most of Civil War II (I didn't even care for the first one. Or the comic for that matter.), but obviously I know that Clint killed Bruce upon Bruce's request. But did the two of them have some kind of deep friendship? I'm not sure why he would ask Clint, wouldn't he ask someone like Rick Jones, Strange or his son or someone else? I'm not sure, am I wrong, or do the two of them have some type of close relationship? Thanks.
The only true explanation is: Bendis and his dislike of Hulk. He never respected continuity of the characters he utilized, so instead of trying to write something that made sense he just wrote something for shock value. Maybe he thought it would appeal to the tiny fraction of people that started reading comics because of the movies.