That article header (and most of the comments below it) are needlessly insulting.
It's not my favourite sport, but I'm amazed at what they do -- precision manouevres underwater, upside down, holding their breath for long stretches, yet keeping in perfect synchronisation.
And yes, they have to do it all with the right (exaggerated) expressions. Like stage performers, they are pretty far from the audience, and in their case, judges. The expressions and gestures are meant to be seen from a distance. Photographed with a tele, they do look unnatural, plus the fact they're gasping for breath.
That said, I do find the routines they do BEFORE getting in the pool campy and (unintentionally?) hilarious. They aren't being scored for those either.