From the fine article itself:

>Within hours, local Homeland Security agents had arrested the offender, who had been raping Lucy for six years.

Are you suggesting that the BBC, the world service arm of a British public broadcaster (that is editorially independent from the state and even the wider BBC), began spending five years filming a documentary across the US, Portugal, Brazil, and Russia, just so that they could secretly support a US government agency half a decade before it became embroiled in controversy?

The claim is that an article was submitted intentionally to manipulate public perception of DHS.

We can't relax the claim to "well, it says DHS found a pedo, so it's propaganda ipso facto, because DHS did something good": they specifically argue the submission was the propaganda, specifically because it'd be absurd to claim it was published as DHS propaganda. (it's an article by the BBC)