I'm sure you know that, but that paragraph looks like a standard blurb that is pasted onto all press releases.

It does come off as farcical, but alas it is not. It's the reality of the situation and nicely illustrates the scale of the issue. Good or bad, Facebook is infrastructure and it's been paid for with privacy.

How exactly is that irony?

Irony: "a state of affairs or an event that seems deliberately contrary to what one expects and is often wryly amusing as a result". One would not expect a webpage condemning Facebook to suggest its readers use Facebook to promote that statement. It is wryly amusing that it does.

Not ironic in the classic sense but it is a humorous coincidence, and it says a lot about Facebook's ubiquity.

Ironic in the Alanis Morisette sense :)

It's ironic because it provides a subversion of expectations: the FTC is releasing a statement in which they are trying to demonstrate some sort of power and authority over Facebook, but at the same time using one of Facebook's product, thereby undermining (in a very minor way) their own statement. It's not deeply ironic, but it's definitely an example of irony.

Source: My partner wrote his doctoral dissertation on irony, so I happen to have picked up an appreciation for the subject.