This didn't start with the generation currently under 18 years of age. I mean not to put too fine a point on it, but the outlandish conspiracy theories everyone is concerned about came from Boomers, Millennials, X'ers and older GenZ'ers. Frankly, the evidence points to all of us having questionable critical thinking skills.
My suspicion is that not only those under 18, but those over 18 as well could use a bit of a refresher on symbolic logic. Also a refresher on assessing the verifiability and relative value of facts.
At the risk of sounding a bit conspiracy theorist myself I would say "authority" is quite comfortable with people not thinking themselves. People aim to be in authority because they think they know what is best for everyone - no thinking required of the hoi polloi.
Edit: I think it would be rather like maths. A lot of people (not around here, but say, business people on LinkedIn) say "I never use the maths I was taught in school so its pointless teaching it" because they do not know how to apply it.
i'd argue that the more common problem is a deficiency in assessing reasonableness or plausibility of facts and claims.
if you feed garbage data into your logic-machine, you'll get garbage results.