It's the same reason Google doesn't let you have more control over the search results. If they give out granular-enough permissions / tooling, then plugins and

It's the same reason Google doesn't let you have more control over the search results. If they give out granular-enough permissions / tooling, then plugins and other tools would be somehow able to make your FB/Google experience akin to a completely different site, with very little control on their part. As a bit of an analogy: They want to be the television that you look at your content through as well as the content provider/curator, but they also don't want to be forced into being just the radio-broadcasting infrastructure provider which is all that they really are if you drill down far enough. Oh and ads, of course.