The general format is about picking a subject (person, brand, company, political party, country) that they are ideologically hostile to, and then picking bits and pieces from the Internet that show that it is baaaaaad. Not that it has a particular downside, but it's baaaad because maybe A, looks like B, I think C, and I heard that D. In this particular piece: the base is not a mushroom (who cares?), Quorn is successful (get'em!!!), I don't like how it tastes (good for you?), and it's owned by a big corporation (see, told you they're evil!). Also, other companies selling fake meat use very complex recipes (you don't say...).
None of that involves actually talking to people or scouting publicly unavailable documents, which is what I perceive as journalism. And they have the guts to claim that "The Guardian’s independent, investigative journalism takes a lot of time, money and hard work to produce."