It's just a very typical clickbait pattern.
"Teen builds online brokerage platform" or "Teen builds bike that goes 100mph" does not cause the same negative anticipation.
The doubt isn't over whether a teen can do 'basic chemistry', it's whether they've 'invented' something; whether they've done anything that someone who doesn't know them/their family/their school and isn't considering their application for something needs to care about. It's whether this is (or was a while before the media got it) news or exciting or a citation for an adult researcher working in the field.
what 14? That's late indeed. The story has to be preschool to be awe-worthy.
For instance: "12/13y old writes the shortest assembly routine to move the head of the floppy drive of Apple II", doesn't sound grounbreaking - even if the code was better/shorter than DOS, itself. Solving massive world problems is a totally different scale.