I imagine embeds would be enabled/disabled per subreddit so mods wouldn't have to deal with it if they didn't want to. A blog that wants to add comments from Reddit would start their own subreddit.
As a former moderator of a default subreddit, I don't think you know what you're talking about here. AutoMod is a useful tool but can only implement basic rules—it's more a supplement to human moderators. And people of course care about things that aren't their jobs.