Kids that age are better BS detectors? No, they aren't.
What they are is cocky, full of themselves, pushing boundaries everywhere against any kind of perceieved authority. The slightest deviation from what they think the world should be is perceived as totalitarian oppression resulting in a reaction of lashing out and rebelling. Rarely is it honest either, as they have their own multiple ulterior agendas of personally trying to gain from it.
Which leaves them open to being manipulated by adults with their own ideological agendas. What they think is being a great BS detector is actually getting played and their buttons pushed.