If any more these shows come along they might as well have their own channel. I believe there are cookery channels, history channels, why not a rogue tradesmen channel?
I'm relatively sure that even those viewers with the mental agility of a boiled banana will have some cognisance that these kinds of programs are not documentaries and are not tasked with fairness or perspective but rather appealing to sensationalism and shock-value. It's tabloid TV. But there can be no doubt some of it seeps in at an emotional level and the general balance gets tipped towards mistrust and caution.
We're all vulnerable to this type of journalism - just like we're vulnerable to crude and blunt advertising. You watch an ad and think it's annoying and ineffective. But two weeks later when faced with two all-but-identical products to chose from, without thinking, you go for the one you've heard of. And not just because you've heard of it either. Tell people something repeatedly and whether they want to or not they will start to believe it.
God help those among us who look vaguely rogue-like.