It has a historical lock because a former moderator placed the lock there. I don't know why he did it. I can't even begin to speculate. But removing the lock would change little: The question is terrible and the user isn't going to fix it.
There's probably still room for a good question along these lines, but this wasn't it. No longer seen in this post are several deleted comments where the poster explicitly stated it was a "test" question and people reacted quite negatively to that. Then he claimed it was based on a real situation, but refused to clarify it so that he could get a proper answer.
I'm pretty sure we'd lose just about nothing if the question were deleted. If anyone else has seen it since the week it was posted, I'd be surprised.