You seem to think that the number of downvotes is relative to the quality of the post. It isn't. The number of downvotes is more correlated with how many people saw the post and *agreed* it should be downvoted. There is nothing about a -4 post that suggests it is worse than a -1 post.
People *think* such a correlation exists but they are simply incorrect. That isn't how things like this work. Yes, the worse a post is the more likely it is to be downvoted but once it has passed the "obviously downvotable" the only thing that matters is visibility.