Imprecise laws give authorities a great deal of discretion about the threat of prosecution. And discretion here is another name for arbitrary power.
Do they mean targeted harassment or libel? Or theft or fraud? Or do they mean playing devil's advocate?
Conflating the harassment of the McCanns with "trolling", a broad term, is just a power grab by an opportunist. It might sound politically beneficial right now but curbs on basic freedoms have blowback. Consequences.
The article reads like satire. I'd expect it out of a backward or totalitarian regime, but not the UK.