I highly doubt they would ever be approved.

Right because they're ads critical of facebook designed to scare facebook users into not using facebook.

Why would facebook green light ads that are detrimental to them?

They're explaining something facebook does without any bias at all. Facebook should be proud to show off their technology! If it's "detrimental" then the problem isn't the ad, so rejecting the ad for that reason is scummy.

It's an ad for a competitor. Why would they do that?

In theory blocking ads from competitors is a violation of anti-trust laws, but when you have more money than god you can just pay the fine.

Well that's a completely different argument. If you want to talk about the part where it makes them look bad, consider an organization similar to the EFF doing this campaign.