"Nah. Representation and, in turn, different viewpoints will make art better. Always."
I'm sure this dude thought this sounded good in his head but actually it's a load of garbage.
"Art" is often created by individuals or smaller groups of people.
So really his talking point is only relevant to collaborative projects with a significant number of people.
Even then a massive collaboration such as a movie or videogame will still have very strict hierarchy with the main bulk of the "art" still being the responsibility of one or two individuals.
Really, the only way diversity focused hiring practices are going to influence the art is if the employees who are not straight, white or male are acting almost like watchdogs on the project. Making sure that the developers follow a specific path and don't end up doing things like having a hot female main character or having a damsel in distress storyline.
It would be like companies having their own internal ratings board where you might, for example, have a load of men doing the heavy lifting of coding and testing and designing but then all the work gets taken to the internal "Feminist Analysis" team who will reject ideas and recommend changes.
This is actually how a lot of game "journalists" and certain purple videogames forums appear to see themselves currently. Just making sure that developers think twice before doing anything "problematic". Just making sure that your game studio won't produce something that the wrong people might enjoy for the wrong reasons.
The fact that this is being done openly on Twitter should be a little troubling.
I think what this dude really means to say is that representation would allow art to be policed in such a way as to not criticize "The Message".